One pegasus, plus one pegasus, equals what? · 3:19pm Feb 8th, 2012
So, it occurred to me while giving someone grammar hints that the generally used plural of "pegasus" - pegasi - is both wrong and right at the same time, but then wrong again. I thought this was interesting enough to cause much ado about nothing on my blog here, and ramble about the etymology of "pegasus" for a while.
Most of the time, when we see the suffix "-us" in English, we assume it comes from Latin, and pluralise it "-i". However, the only words really routinely found outside legal, medical and scientific usage are octopus and platypus, and these are actually both Greek in origin (meaning "eight foot" and "flat foot" respectively), so "octopi" and "platypi" are both wrong - the correct plurals as far as the words' origins are concerned are "octopodes" and "platypodes". However, many authorities consider the purely English plurals ("octopuses" and "platypuses") to be correct, since "octopus" came to English from Scientific Latin, and "platypus" is a neologism, and consequently, neither have any real connection to actual ancient Greek. While the words sound awkward and make hellenophiles like me cringe, they aren't wrong.
So what does this mean for pegasi? I mean, pegasuses? Well, "pegasus" comes from Greek. So that means it's pegasodes, right? Uhm, no. The Greek form of pegasus is "pegasos" (Πήγασος), which pluralises as "pegasoi". However, since we're converting everything back to English anyway, 'oi' in Greek usually translates as 'e' (e.g. "oikos" is the root of "eco-" as in ecology or economy), which would leave us with "pegase" in English. But then, because of the way English is read, most people would read that as peg-ayss (or "pɛgeɪs" if you can read IPA). So the easiest way to write this in English, while not including extra symbols, is to just write "pegasi", if you hadn't arrived on that from contraction of "pegasoi" in the first place. So that settles it then! The plural of pegasus is pegasi, agreeing with its Greek origin and only coincidentally looking like faux-Latin.
If you'll look back at Greek mythology, Pegasus referred not to many horses, but only to one. Pegasus was a white, winged stallion, fathered by Poseidon and foaled by Medusa. The word 'Pegasus' is a name, not a descriptor, so strictly speaking, it shouldn't have a plural at all! The winged ponies in My Little Pony are named "Pegasus ponies", after the mythological horse they resemble! So if you wanted to be really correct, you shouldn't call one of them a pegasus in the first place, they're a Pegasus pony.
While "Pegasus ponies" is the most technically correct term, it's highly formal. This is fine for in-depth descriptive passages and poetic usage, but the vast majority of usage in both stories and the show are in dialogue and brief description, which needs a term less crammed with syllables. And the most logical contraction of "Pegasus pony" that doesn't remove meaning, is "pegasus", in lower case to distinguish it from the race's namesake. So all in all, our original assumption as in fact correct - the plural of pegasus is pegasi.
Like I said; much ado about nothing.
Thanks for posting this, it's something I had actually wondered about for a while. It had gotten to the point where I was rearranging sentences to avoid the plural form, or actually using "pegasus ponies" since that was the only thing I really knew was correct.
It also should be noted that "pegasi" sounds relatively normal, at least to stargazers, because we use it in astronomy to designate stars in the constellation Pegasus: Alpha Pegasi, Beta Pegasi, etc. On the other hoof, that's not a plural form at all. Alpha Pegasi is one star.
10911 Ah, there's something else again! That version of Pegasi comes from the Bayer designation of star names, combining a Greek letter with the Latin name of the constellation, essentially meaning "first of Pegasus" and such. Since that falls under Scientific Latin (the only place you'll find such gross mixing and matching of Greek and Latin), it sits at something of a tangent to the whole plurals debate. Though it is interesting to see how yet ANOTHER variation of the word ends up reading the same.
Salvete omnes,
The Romans themselves borrowed the Greek Πήγασος (Pegasos) and turned it into Pegasus, thereby Latinizing it and treating it as a Latin word of Latin's second declension. The Latin (nominative) plural is indeed pegasi. The Romans even used this plural. Pliny the Elder wrote: "sunt mirae aves cornutae (in Africā) et equinis auribus Pegasi" ("There are wonderful horned birds (in Africa) and Pegasi with equine ears").
The Pegasi in Alpha Pegasi and Beta Pegasi and such is not the (nominative) plural! It is actually the genitive singular, and in this case can be translated as "of Pegasus" (as mentioned earlier).
Curate ut valeatis.