The claim: Sosie is a diminutive of Susan

If you’ve heard of the name Sosie, there’s a good chance it’s because of the actress Sosie Bacon, daughter of Kevin Bacon and Kyra Sedgwick.

Let’s say you’re watching something with Sosie Bacon in it, and you think her name sounds interesting, so you google “sosie name” – what you’ll find is a bunch of baby name websites telling you that Sosie is a nickname for Susan. Here’s a screenshot from Nameberry:

Screenshot of the listing for the name Sosie, saying "Sosie: Diminutive of Susan"

As of March 2024, Nameberry, BabyNamesPedia, and all explicitly say Sosie is derived from Susan, Susanna, or Susie. MomJunction does not directly connect Sosie to Susan, but implies that Sosie must be a diminutive of either Susan or Shoshana by listing Sosie as being of Hebrew origin and having the meaning “lily”. (The commonly accepted origin of Susan and Susanna is as English variants of the Hebrew name Shoshana meaning “lily”, see DMNES and Wiktionary.)

This all seems pretty compelling. Any reasonable person looking up the name Sosie would likely stop there, and conclude that Sosie is in fact an obscure nickname for Susan, possibly vintage like Suzette or historical like Sukey. 

However, I am not a very reasonable person when it comes to names, and I could not stop there, because something is missing in all these name website entries. There is not a single person mentioned named Susan and called Sosie. How many Susans have you met in your life? How many book or TV or movie characters called Susan have you encountered? How many different nicknames and spelling variations of Susan and Susanna and Susie have you seen? Have you ever heard of a Susan (or Susanna) who was called Sosie?

I have not. 

So I began to wonder if Sosie is really a nickname for Susan, and if not, what the real origin of the name is, and why so many baby name websites think it is a diminutive for Susan. I got pretty stuck on this, spent several days’ worth of free time researching it, and now I’m going to tell you everything I found out. (Or you can jump to the conclusion for the short version.)

Looking for Susans called Sosie

My first step was to check the popularity of the name Sosie in the US Social Security Administration name data. If a nickname is common enough, it starts to get occasional use as a given name; both from people being given the diminutive as their full name, and because some older records list people under nicknames even if their parents did give them a different formal name. 

If Sosie was a common nickname for Susan at any point since 1880, we would expect to see some Sosies in the data, starting from whenever the nickname emerged. This is not what we see. Here’s the graph from Nancy’s Baby Names:

Graph of number of babies named Sosie born in the US over time. The link before this image goes to a page that lists the data numerically in a chart.

As you can see, the first year that Sosie broke the 5 baby threshold to get included in the SSA data was 2000, and there have been a handful of baby Sosies most years since then.

For contrast, let’s look at the graph for Susie:

Graph of number of babies named Susie born in the US over time. The link before this image goes to a page that lists the data numerically in a chart.

Unlike Sosie, Susie has been used as a name since the beginning of the US data, and has peaks around 1950 and 1960, when Susan was wildly popular. This is exactly what we would expect to see for an established nickname for Susan.

This data suggests that if Sosie is a nickname for Susan, it’s an obscure one – but even a fairly uncommon nickname should leave some trace, so maybe if we dig deeper we can find something?

For comparison, let’s consider Sukey. Sukey, sometimes spelled Sukie or Sookie, was a nickname for Susan (or Susanna) used for a couple decades on either side of 1800. The Sukey spelling has never made it into the US name data, although there have been a couple Sookies and Sukies in more recent years. Although Sukey faded from usage before the SSA records began, it’s easy enough to find evidence of historical and literary figures named Sukey. There’s a Susan “Sukey” Richardson (b. 1810) who escaped slavery and became active on the Underground Railroad, a Sukey (b. ca. 1795)  who was enslaved by James and Dolley Madison, a Sukey Vickery Watson (b. 1779) who was an author and appears to have been named after her mother Susannah, a character named Sukey in one of Jane Austen’s teenage works, and a character in a nursery rhyme. There are also plenty of Susans called Sukey on genealogy websites (1, 2, 3).

If Sosie (like Sukey) is an obscure historical nickname for Susan and Susanna, then we should be able to find similar evidence of historical and literary figures going by Sosie. I couldn’t find any evidence of literary characters called Sosie that were associated with the names Susan or Susanna (more on other literary Sosies in the next section). When I searched genealogy websites, the results were initially promising. There are several records from the US 1940 Census on that appear to list Susans called Sosie (1, 2, 3, 4, 5, among others) – awesome, right? Here’s a whole bunch of Sosies, all of whom seem to have been Susans. Evidence of Sosie as a nickname for Susan!

However, for every single record like this that I found, when I clicked through to the scan of the actual handwritten record, it seemed to me that the original record actually said “Susie”, and that “Sosie” was a transcription mistake when the record was digitized. 

For example, here’s the 1940 census record that has recorded as Sosie Killen:

Screenshot of a scanned image of a handwritten census record. The important entry is highlighted in yellow. It is written in cursive, and says "Susie".

Now, I can see why that might look like an “o”, but personally, I’m pretty convinced it’s actually a “u”.

For every Sosie I found on, I checked the handwriting on the original document and also searched for the same record at to see how it was digitized there (for example, here’s Susan Smith, #5 on my list above). Every single time, I concluded that the record was an instance of misreading the handwriting, and the person in question actually went by Susie, not Sosie.

I have zero evidence for this, but I suspect these digitization mistakes on contributed to the proliferation of name websites listing Sosie as a diminutive of Susan. My guess is that somebody heard of Sosie Bacon, wanted to add Sosie to their name directory, thought it sounded like it could be a diminutive for Susan, googled “sosie susan” or something similar, found the listings, and took that as evidence for Sosie as a nickname for Susan.

Not only did I not find evidence of any Susans-called-Sosie on genealogy websites, I couldn’t find any evidence of real human beings named Susan (or Susanna) but going by Sosie on baby name forums either! I found several posts on Nameberry and Reddit where people recommended Sosie as a nickname to users asking for ways to modernize Susan, or using Sosie as a nickname for Susan in create-a-family type games, and I found a couple people saying that they planned to name a future child Sosie, but I did not find a single person who said that they knew anyone named Susan (or Susanna) who was called Sosie.

So where does this leave us? Several hours of research in, and absolutely no evidence of any human beings ever being called Sosie as a short form of Susan (or Susanna). Of course, that doesn’t prove that no Susan has ever been called Sosie (if you know any Susans called Sosie, please leave a comment!) but I think this is pretty convincing that if Sosie is a nickname for Susan, it’s even more obscure than Sukey, and likely would be considered more of a unique family nickname than an established diminutive.

So where did Sosie come from?

If you go back to the SSA data, you’ll recall that Sosie didn’t make it into the US name data until 2000. That means that every single Sosie in the SSA data is younger than Sosie Bacon. Additionally, many of the Sosies in the data were named after baby name websites started listing Sosie as a nickname for Susan – for example, according to the Internet Archive Wayback Machine, Nameberry listed Sosie as a diminutive for Susan as early as March 2012, with a reference to Sosie Bacon. Taking those two points together, there’s a good chance that most of the young Sosies in the US today were named (directly or indirectly) after Sosie Bacon, whose very famous parents have been mentioning her in interviews since she was very young.

If it’s not actually an uncommon but established diminutive of Susan, where did the name Sosie come from? Did Kyra Sedgwick and Kevin Bacon invent it, or did they get it from somewhere?

To answer this question, I tried to track down any use of Sosie as a name that predated Sosie Bacon. There were three sources that were very helpful in this search:

  1. Searching Google Ngram Viewer and Google Books
  2. Emailing Nancy Man of Nancy’s Baby Names
  3. An Appellation Mountain post from 2009

Some of the results from Google Books didn’t seem to be related to Sosie as a name (for example, there’s apparently some kind of seismology technique or method called mini-sosie, and I found a single reference to a racehorse called Sosie, but racehorse names often have very little connection to human names), but I found several interesting instances of Sosie as a name. I’ll try to lay them out as clearly as possible.

A Roman family name

This one took me a lot of searching and working backwards to arrive at, so I am going to spare you the confusion and work forwards.

Sosia (or Sossia) is a Roman gens, which is a kind of family or clan name. The best information I could find about the origin of this name is that it might be borrowed from the Ancient Greek name of a river in Sicily. Roman naming conventions can be confusing, because they look a lot like modern European names but work very differently, but for our purposes, all we need to know is that male members of this family usually have Sosius as their second name, and female members of this family often have Sosia as their first name. (Where “second” and “first” refer only to the position, these are not equivalent to modern first names and middle names.) This leads us to a couple possible sources for Sosie as a given name.

First, in the Appellation Mountain post about Sosie, Abby mentions “a French Saint Sosie from the 300s, a victim of the Diocletian persecutions” – I believe she’s referring to Sossius (also written Sosius), who was actually from Naples, but whose name seems to be given as either Sosie or Sozy in French. It seems very probable that St. Sossius’ name comes from the Roman gens, and I believe that is what this Italian dictionary of saints says (thank you Google Translate). Although not impossible, the French name for an obscure male saint does not seem like a very likely origin of Sosie as a girls’ name in the US.

Second, there is a character named Sosia in Platus’ play Amphitryon. Since this is a Roman play from c. 190–185 BCE, I think this name is very likely connected to the Roman gens. Platus’ Amphitryon inspired a later French play, also called Amphitryon, written by Molière in 1668. In French, the Sosia character becomes Sosie, and ultimately gives rise to sosie as a French word meaning “lookalike”. Later still, another French playwright named Jean Giraudoux retold the story as Amphitryon 38 in 1929. Both the Moliere and Giraudoux plays had English translations published and performed in the 1930s. This is a possible source of Sosie as a feminine given name in the US, although I don’t think it’s very likely as the Sosie/Sosia character in Amphitryon is male.

Interestingly, despite its pleasant sound, Sosia as a Roman gens does not seem to have given rise to Sosia as a feminine given name in Italy or elsewhere in Europe. (Contrast this with other gens like Aemilia, Aurelia, Caecilia, Calpurnia, Claudia, Cornelia, Flavia, Julia, Lavinia, Lucretia…) Searches for “sosia name”, “sosia name italy” etc. mostly brought up last names or dictionary entries about sosia or sosie as words meaning doppelganger.

A Navajo family name

When I was using Google Ngram Viewer and Google Books to search for Sosie as a name in books published before Sosie Bacon was born, I found a character named Sosie in a Wild West genre novel from 1928 called Wild Horse Mesa, by Zane Gray. I did not read very much of the book sample, because the little I read struck me as being racist and sexist, but the Sosie in this book seemed to be (intended to be) a Navajo woman (based on some dialogue near the first instance of “Sosie” in the text). Although I didn’t really trust the accuracy of anything in this book, that was enough for me to search “sosie navajo name,” just in case.

From there, I found that Sosie seems to be a variant spelling of the Navajo family name Tsosie. For example, both Tsosie and Sosie appear as middle or last names on lists of Navajo code talkers from World War Two (1, 2, 3). Family Search says that Tsosie as a family name developed as an Anglicized version of the Navajo personal suffix -tsʼósí, which means “slender” or “skinny”. This etymology is supported by a line from the poem “No Parole Today” by former Navajo Nation Poet Laureate Laura Tohe:

Tsosie. Ts’óhsí means Slender.

(The poem is from Tohe’s PhD dissertation, and is quoted in Liliana Elliott’s very interesting Honors Thesis about name alteration at a residential school.)

I did not find examples of Sosie being used as a Navajo given name (other than that book), but Tsosie/Sosie seems like a common enough family name that perhaps it has occasionally inspired a given name. If you know more about Navajo names than I do (a low bar) and have any insights here, I would love to hear from you in the comments.

A Jewish name

Midway through my Sosie journey, when I was feeling quite stuck, I emailed Nancy Man from Nancy’s Baby Names to ask if she had any ideas. Nancy was my first thought for seeking help because she has a knack for tracking down the original sources of rare names, and she very kindly responded (although her email got caught in an overzealous spam filter for a while). Here’s the relevant portion of Nancy’s email to me:

I wonder if Sosie isn’t a Yiddish name?
Doing records searches for the first name Sosie, I noticed that a lot of the surnames seemed to be either German or Russian (Polish?), which made me think that perhaps there’s a Jewish connection here.
So I did some internet searches along these lines, and found a few interesting things — such as this academic paper about Americanized Jewish names that lists Sosie as an equivalent of Sosye and Sosje, and notes that all three derive from the name Sore. (on page 89)
I eventually found a couple of these names in the “Dictionary of American Family Names,” which mentioned (in the entries for the Jewish surnames Sosin and Sorin) that Sosye was a pet form of the Yiddish personal name Sore, and that Sore was derived from the Hebrew name Sara.

(Email from Nancy Man)

The master’s thesis Nancy found is very interesting – I read it in its entirety and enjoyed it quite a lot. The author (Jason Greenberg) analyzes data from petitions for naturalization from 1914 to 1935 for people who listed “Hebrew” as their race and were born in non-anglophone countries. Sosie appears in Appendix C. If I understand this table correctly, that means there was one person in the dataset whose name was listed as Sosie on the passenger list of the ship she immigrated on, and in order to group names together, Greenberg has interpreted Sosie as a variation of Sore, on the basis of A Dictionary of Ashkenazic Given Names by Alexander Beider. As Nancy says, Sore is an Ashkenazic variation of the Hebrew name Sara, which means “lady” or “princess”  (1, 2, 3).

Another possible origin of Sosie as a Jewish name comes from a comment on the Appellation Mountain post from someone named sosie who says:

this was/is my nickname. My first name is actually Shoshanna… It is a cute nickname but I have been trying to dump that name since I was kid because people have such a hard time pronouncing it and they always ask me what it’s short for? …I try to go by Shoshanna with anyone other than old friends and close family.

Next, I borrowed Alexander Beider’s A Dictionary of Ashkenazic Given Names on interlibrary loan. I wanted to see what was in the entry for Sore that made Greenberg group Sosie with Sore in his thesis, and I wanted to see if there was anything in the entry for Shoshana (spelled Shoshane in this book) that suggested a connection to Sosie. Sosie does not appear in the index, but the entry for Sore lists Sosa, Sose, Sosye, and Sosia as variants/diminutives, and Sosie does seem like it belongs in this group. The entry for Shoshane lists Szosia as a variant, and notes:

The names Sosye and Soske can either be derived from Sore (see the entry for Sore) or represent forms [of Shoshane] resulting from the sabesdiker losn in NEY.

A Dictionary of Ashkenazic Given Names, A. Beider, 2001, p. 570

From the introductory material at the front of the book, “NEY” is an abbreviation for Northeastern Yiddish, and sabesdiker losn is a linguistic term for a type of phonetic shift that happens in that dialect – Beider is saying that in that dialect of Yiddish, there’s a pattern of words that initially had an /sh/ sound being pronounced with an /s/. So, if Sosie is a variant of Sosye (which seems likely to me, although I have some questions about pronunciation), then it could be a nickname for either Sore or Shoshana.

Whether it comes from Sore or Shoshana, Sosie does seem to have documented usage as a standalone given name for Ashkenazi Jews. Searching for “Sosie” as a given name on JewishGen brings up thousands of records, and the Holocaust Survivors and Victims Database has 80 exact matches for people with the given name Sosie and 54 exact matches for people with the given name Sosi. Quite a few countries come up too (Romania, Switzerland, the Netherlands, Austria…) so although Sosie wasn’t the most common name, it does seem to have been geographically widespread among European Jews in the early 1900s.

Before leaving this section, I want to make the point that Sosie being a nickname for Shoshana is not the same thing as it being a nickname for Susan. Although Susan is derived from Shoshana, it is a different name, traditionally used by a different group of people, with a different set of nicknames. We would not list Sue as a nickname for Shoshana, or Shosh as a nickname for Susan.

An Armenian name

The Appellation Mountain post on Sosie has a comment from someone named A that I will quote in its entirety:

Sosie is an ancient Armenian name, not very common these days, the name of Armenian queen, who was the wife of Aram II- latest was the king of Armenia around 3000 years ago. She was so beautiful that pregnant women believing the old legend tried to face her so they would give a birth of beautiful children. the queen was the mother of legendary Armenian king Ara the Handsome, who was killed by the queen of Babylon, Shamiram. Queen Sosie planted plane tree garden that was named after her in Armenian as sosi trees.

It is a very beautiful name, not a nickname as such described above. And the association with the beautiful queen should you all Sosie’s make feel proud and love it, as it’s Indo-European origin, you can meet it in France as a city and historical people and in Sanskrit as well.

I tried to check all the claims made in this comment. Starting with the end, there does seem to be a Sanskrit word transliterated as śoṣi, but I do not think this has any connection to Sosie as a name, Armenian or otherwise. My guess is that the French city the commenter is referring to is Saint Sozy, which ties back to the Roman gens Sosia (see above), and I could not find any connection between the Roman name and the Armenian name.

As to the story about Queen Sosie and plane trees being called sosi trees after her, this seems to be true. The Armenian word for plane tree is indeed սոսի (sosi). The queen seems to be more commonly referred to as Sosem (1,2), but the second link repeats the story about her famous beauty and plane trees being named for her.

It also seems clear that Sosie is an Armenian feminine given name, although transliterations vary. There is a Sosie mentioned in the book Out of My Great Sorrows, a biography of the Armenian American artist Mary Zakarian by her nephew and niece Allan Arpajian and Susan Arpajian Jolley (it’s hard to tell from the previews, but I believe this Sosie was Mary’s sister and born in the US in the 1920s). There is Sosi’s Armenian yogurt, Sosse and Sossi on this list of Armenian names, and the freedom fighter Sose Mayrig (1,2). Sosie, Sosi, Sose, Sossi, and Sosse all appear to be transliterations of the name Սօսէ. The given name is spelled differently from the word for plane tree (սոսի), but multiple sources agree they’re related and I don’t speak Armenian so I will have to accept that.

To be completely thorough, I wondered whether the Armenian name Sosie and the Hebrew name Shoshana might have a common origin – after all, they’re both from plant words and the languages are from nearby parts of the world, so it’s at least more believable than a connection between Shoshana and the Navajo name Tsosie. According to wiktionary, Shoshana (meaning lily or rose) is from Egyptian zšn meaning lotus. Now, you might think “Aha, we’ve already moved from lily to lotus, maybe somehow we can get to plane tree!” – but no, it turns out the Armenian word for lotus is շուշան (šušan), from the Egyptian zšn (Wiktionary, Google Translate). So, as far as I can tell, the Armenian name Sosie has no connection to Shoshana (or to Sore).

But what about Sosie Bacon?

So now we have a couple possible sources for Sosie as a feminine given name in the US. Which one explains Sosie Bacon’s name? 

I’m not going to go into much detail in this section, because it deals with living people, some of whom are not public figures. In summary, I dug through many, many, many interviews where Kevin Bacon and/or Kyra Sedgwick mentioned Sosie, and eventually found one that briefly discussed the origin of her name. Based on this interview, Sosie Bacon was named after one of her parents’ acquaintances, and my guess is that that Sosie might be either Jewish or Armenian.

Conclusion: Sosie is NOT a nickname for Susan

I found evidence that Sosie is:

  • A French form of masculine names deriving from the Roman gens Sosia (used primarily for specific historical & literary figures)
  • A French word meaning “lookalike”, based on the Roman name
  • A variant spelling of the Navajo family name Tsosie meaning “slender”
  • A Jewish feminine given name, probably originating as a diminutive for Sore (a form of Sara, “princess”) and/or Shoshana (“lily”)
  • An Armenian feminine given name meaning “plane tree,” associated with a famously beautiful semi-legendary queen

I did not find any evidence of Sosie as a diminutive for Susan or Susanna.

To be clear, I am not claiming that no one on earth has ever been named Susan (or Susanna) and gone by Sosie. There are plenty of people in the world with unique nicknames that may not leave any trace. For example, if Elizabeth II hadn’t belonged to one of the most famous families in the English-speaking world, most of us would never have known that her family nickname was Lilibet, and Lilibet would likely have never made it into the SSA name data

What I am saying is that Sosie as a diminutive for Susan is at best so uncommon as to be undetectable, while Sosie as an Armenian name and Sosie as a Jewish name are comparatively well-documented. Given this, I think name dictionaries and directories that currently list Sosie as a Susan diminutive should consider changing their listings. (Unless they have some evidence that I couldn’t find, in which case, please share!)

All that being said, I have one final question: Could Sosie be a nickname for Susan? Even if we accept that Sosie doesn’t have a history of being used as a diminutive for Susan, could parents looking to pair Susan with a more modern nickname start using Sosie? Sure! It’s at least as reasonable of a nickname as Sukey, so I say go for it. If anyone asks where you got it from, send them this post. 🙂

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