capit

The root capit comes from Latin caput, capitis — simply "the head." But the head is not just a body part; it sits on top, it leads, and you can count it. Those three facts about a head generated an entire family of English words, and once you see which of the three is in play, the whole family snaps into focus.

The head leads. The person at the head of a group is in charge. Late Latin capitaneus ("chief one") gave English captain — the head of a ship or a team. The same Latin word traveled through French twice and arrived in two different shapes: chief (the head of a clan or department) and, much later, chef — originally chef de cuisine, the "head of the kitchen." Chief and chef are literally the same word; French softened the hard Latin c into a sh sound, and English borrowed it once early (chief) and once late (chef). The adjective capital also rides this sense: the capital city is the "head" city of a country, and a capital crime is one serious enough to cost you your head.

The head is the top. Because the head is uppermost, capit came to mean "topmost, principal." A capital letter is the big one at the top of a sentence; capital, in money, is the principal sum that everything else grows from. A chapter (from Latin capitulum, "little head") is a section that sits under its own heading. To capitulate once meant to draw up terms of surrender under headings, point by point — and to recapitulate is to go back over those main heads, i.e. to summarize.

The head can be counted. One person, one head. A capitation is a tax levied per head, and per capita means "per head" of the population.

Falling head-first. Add prae- ("before, in front") to caput and you get the image of pitching forward head-first. A precipice is the cliff edge you could plunge over head-down; precipitate means to throw something headlong — to make it happen suddenly — and precipitation is what falls headlong out of the sky: rain and snow.

The trap to avoid: capit (head) looks like cap (take, seize), and the two are cousins from the same prehistoric root, but they split early. If the meaning is about leading, topping, or counting a head → capit. If it is about grabbing or holding → cap (capture, accept, receive).