Losing a Game of Ghost

I

The nominative personal pronoun and the most-often used word in speech ("the" wins in print), "I" clearly has to be related to either the Germanic side of English-- German currently uses "Ich", and Dutch has "ik"--or the Romance side, with Italian "io" as a representative. Which was it? Both, as it happens. It started as Latin "ego", "I", and eventually mutated into "ec", which after one of those inevitable vowel shifts became Old English "ic".

Id

Most people likely know that the id is, in Freudian theory, the part of the mind that's responsible for demanding the instant gratification of impulses (kept in check, luckily, by the ego and the superego). But what does it actually mean? Piece of cake: it's the Latin word for "it". And it isn't what Freud called it: he used German words for his three divisions of the psyche. "Es" is the German for "it", and "das Es" means "the 'it'", which is how he expressed it. (The other two words were "das Ich", "the 'I'", and "das über-Ich", "the super-'I'".) In English, we use the Latin translations of his words.

-ide

This combining form is seen in all manner of chemical compounds: sodium chloride, for example, which is table salt. "-Ide" has a truly oddball genesis. The word "oxygen" comes from the Greek "oxus", "sharp, acidic", and the French combining form "-gen", which is related to our "generate", from the Latin "generare", "to produce, to give birth to": "oxygen" literally means "acid-producer". The French word "acide" is clearly the root of our "acid", and they mean the same thing. The suffix "-ide" comes from "oxide", which is to say the French words "oxygene" plus "acide" portmanteaued together: that is, "acid" plus "acid".

Ides

"Beware the ides of March!" is so much a part of the language that most people don't know that every month had an ides. It simply refers to the eighth day following the nones; that is, the fifteenth day of March, May, July, or October, and the 13th day of the other months in the Roman calendar. The ancient Roman calendar was a very flexible thing (think of how Easter floats around our calendar, and imagine the whole year's working like that): the only invariant days were the kalends, the first day of the month, and if you think that's where the word "calendar" came from, you're right.

So: happy ides of May.