Some people have claimed that the word corduroy comes from the French phrase corde du roi, which means "cloth of the king". Interesting hypothesis, but nobody is recorded as ever having said that in French. So, forget that. The most likely theory is that corduroy comes from the English word cord and duroy, an obsolete term for ab obsolete type of fabric. Duroy is so obscure and antiquated that, while it is attested, there is no discernible etymology. Meanwhile, cord has a very widely accepted origin. It comes from French corde (yes, that corde; the alleged "cloth" meaning is very rare), with the same meaning, from Latin chorda, a word which literally meant "cat-gut" as many cords were constructed out of animal intestines. Through Greek khorde, this comes from Proto-Indo-European ghere, meaning "intestine".

In Middle English, debt was spelled dette, and in Old French, it was spelled dete. However, when we trace it to Latin, it was debitum, from the verb debere, which had the meaning of "to owe". This is the interesting part: Middle English scholars figured that, based on the Latin spelling, our word for debt was missing a b, so they inserted a b into dette and it evolved into the modern term, which is why there's a silent b in debt today. Other similar words, like subtle and doubt, developed similarly: because of a Latin root with a b in the past, we're now stuck with weird spellings. From debere, we can identify the prefix de-, meaning "from", "of", or "away", and habere, the verb for "to have". Through Proto-Italic, this derives from the Proto-Indo-European reconstruction gehb, meaning either "to give" or "to receive" (so debt can be interpreted as "to give away"). Surprisingly, usage of the word debt seems to have flatlined since the 1800s.

Aristophanes is now one of my favorite people in history. Well-renowned for his studies of Homer, he became head of the library of Alexandria around 200 BC. But there was a major problem with language at the time. It was hard to understand! There were no spaces, lowercase letters, or punctuation. This could get quite annoying, so Aristophanes decided to invent a whole new system of punctuation. Specifically, three different types of spaces between parts of sentences, but he was a pioneer in the field. The "comma" was the shortest pause, and was notated by a single dot in the middle of a line of text (this later drifted down and developed a curvature). The "colon" was the intermediate pause, and was notated by a single dot at the bottom of a line of text (another, middle dot was later added). The "period" was at the top of a line of text and was the longest kind of pause (this dropped to the bottom, of course). Although this was very rudimentary, all other punctuation would come from or be inspired by Aristophane's three pauses, so this is very cool.

Unsurprisingly, an ellipse (meaning "oval") and ellipsis (the three-dot punctuation...) come from the same root. The plural of both is ellipses, anyway. They come from the Latin word ellipsis, which meant "omission" (the first because of some math-y thing to do with the base of a cone and the second because an ellipsis is, after all, an omission, implying something else). Ellipsis is from Ancient Greek elleipsis, which had about the same meaning, from elleipein, which literally translates to "to leave out". Here we can eliminate the prefix en, meaning "in", and we're left with the verb lepein, meaning "to leave". Most likely, lepein can be reconstructed to the Proto-Indo-European word leikw, also with a definition of "leave". So both a form of punctuation and  a shape are leaving a lot out. Surprisingly, ellipse is used in literature far more than ellipsis or ellipses.

In primary school, I was always taught that a simile is a comparison using the terms "like" or "as". I've always thought of it as an obvious metaphor, but the first way of looking at it is far more etymologically correct. Simile was borrowed in the fourteenth century from Latin, where the word was spelled the same and essentially meant the same thing. This is from similis, which literally meant "like" (in the context of a comparison, not the word used in the comparison, sadly). Through Old Latin and Proto-Italic, all of this traces back to the Proto-Indo-European reconstruction sem, meaning "together". Unsurprisingly, similis is also the etymon of our word similar, through a brief pit stop in Old French, and simulate, through Latin simulatus, meaning "to imitate". So, a simile is like a plant: it has a really cool root!

We say tick-tock and not tock-tick, we say ping-pong and not pong-ping, and we say tic-tac instead of tac-tic. There are countless more examples, from spic-and-span to flim-flam to jibber-jabber to King Kong. Surprisingly, there's a reason why the reverse of these common phrases sounds off to our ears. In linguistics, it's known as the rule of ablaut reduplication. In any grouping of two to three words with the corresponding vowels, our brains naturally find it easiest to think in terms of I, A, and then O. That's why "big bad wolf" is said that way instead of following the more grammatically correct "bad big wolf" (as it's customary to put opinion adjectives in front of size adjectives), and that's why all these other variations exist. It's our own minds tricking us into what's "right"; just another quirk of the human race.