A recent discussion on Twitter about whether the line “I’m gonna have to science the shit out out of this” was in Andy Weir’s book The Martian or was only found in the movie reminded me of one of my favorite facts: science and shit are related. So let’s science the shit out of this etymology.

It all starts (as so many of these things do) with Proto-Indo-European. The root *skey meant ‘to cut, split, separate’. The extended form *skeyd became scit in Old English. The sc sequence was originally pronounced /sk/ in Old English and other Germanic languages, but it eventually became pronounced /ʃ/ (the “sh” sound) in Old English. The sh spelling came later under the influence of French scribes. But despite those minor spelling changes, the word has remained virtually unchanged in over a thousand years. You could travel back to Anglo-Saxon times, and they would understand you if you said shit.

So how did a root meaning ‘to cut, split, separate’ come to mean ‘feces’? From the notion of separating it from your body. The same metaphor is found in the Latin excrementum, which employs the unrelated root meaning ‘to sift, separate’.

This means that shit probably started out as a euphemism. Speakers of Proto-Indo-European or Proto-Germanic may have talked about needing to go separate something rather than use a more unsavory term. In English, shit was fairly neutral for a long while and apparently didn’t become taboo until around 1600, at which point it mostly disappeared from print. It isn’t found in Shakespeare’s plays or in the King James Bible.

Euphemisms often become sullied by the connotations of the thing they’re euphemizing, which leads to the need for new euphemisms, a process sometimes called the euphemism treadmill. So even if shit started life as a polite way to talk about defecation, it eventually became a rather crude one.

(By the way, the “ship high in transit” etymology is pure . . . well, you know. Kory Stamper’s excellent book Word by Word covers this and other bogus acronymic etymologies in more detail.)

In Latin, the PIE root *skey gave rise to the verb scire ‘to know, to understand’. It probably developed from ‘separate’ to ‘distinguish’ or ‘discern’ (that is, ‘tell things apart’) and then to the more general sense of ‘know’.

A noun form of the present participle of scire, scientia, originally meant the state of knowing—that is, ‘knowledge’. Scientia became science in French, which was then borrowed into English. In English it came to mean not just knowledge but the body of knowledge or the process of gaining new knowledge through the scientific method.

The Latin scire gives us a whole bunch of other words too, including conscience (from conscire ‘to know well, to be aware, to have on one’s conscience’), conscious (also from conscire), prescient (‘knowing beforehand’), and nescient (‘not knowing, ignorant’). A related form, nescius is also, surprisingly, the origin of nice, which is a great example of just how much meanings can change over time. Though it originally meant ‘ignorant’, it shifted through ‘foolish’ to ‘lascivious, wanton’ to ‘showy, ostentatious’ to ‘refined’ and then ‘well mannered’ or ‘kind’. The Oxford English Dictionary records many more obsolete senses. A different descendent of *skey yielded the Latin scandula, which later became scindula and was then borrowed into English, where it became shincle and then shingle (from the notion of splitting off a thin piece of wood).

In Ancient Greek, the root *skey yielded schism (meaning a division between people, often in a religious organization) and shizo-, as in schizophrenia (literally ‘a splitting of the mind’).

Back in English, *skey also yielded shed (meaning ‘to cast off’, as in shedding skin, but not the shed meaning a storage building). It probably also gave us sheath (from the notion of a split piece of wood in which a sword is inserted). The Online Etymology Dictionary says it also gives us shin (from the sense of ‘thin piece’, though that’s a little opaque to me). And it’s the source of the word share, from the notion of dividing what you have with someone else. It also gives us shiver (in the sense of a small chip or fragment of wood), which still appears as a dialectal word for ‘splinter’.

In Old Norse, *skey yielded skið also meaning ‘piece of wood’, which eventually gave us the word ski.

And *skey appears to be a variant of another root, *sek, meaning ‘to cut’, which gives us a whole host of other words like section and segment and saw, but I should probably cut this post off somewhere and save some things for another day.