Epsilon’s Fat Brother: A Greek Alphabet Joke

The Case of the Fat E: A Brief and Unscientific Expansion of the Greek Alphabet

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There is a moment, somewhere around the fifth letter of learning Greek, when a perfectly reasonable person looks at the word epsilon and thinks: hold on. If this is “E” plus psilon, then psilon must mean something, and if psilon means something, then surely there is a whole family of E-words waiting to be discovered. A zeta-psilon. A gamma-psilon. The mind, once it spots a pattern, does not like to be told the pattern is a one-off.

I am here to deliver the bad news and then, immediately afterward, to make the situation much sillier.

The Disappointing Truth

Epsilon does break down into “E” plus psilon. The villain in our story is that little Greek word ψιλόν (psilón), which does not mean “the letter E does this” but rather “bare, plain, simple.” So epsilon is, with crushing literalness, just “plain E.”

The reason it needed a name at all is one of history’s quieter bureaucratic decisions. By the Byzantine era, the letter E and the two-letter combination αι had drifted into sounding exactly alike, both landing on a flat…