cap

The root cap comes from the Latin verb capere, "to take, to seize, to grasp." Picture a hand closing around something — that physical act of grabbing hold is the seed from which a huge family of English words grew. Romans used capere for catching prey, seizing a city, taking in food, and grasping an idea. From this one verb, English inherited words about receiving, capturing, containing, and even conceiving.

The reason this root looks so different from word to word is that Latin reshaped it depending on prefixes and tense. capere gives the base form cap (capable, capacity). But the past participle was captus, which gives capt/cept (captive, accept, concept). And when capere combined with a prefix, the short vowel weakened: a turned into i, so cap became cip (anticipate, participate, recipient). In the same way, the past participle capt- became cept after a prefix. Finally, verbs that traveled through French took the form -ceive, while their nouns kept the Latin -cept (receive → reception, conceive → conception).

Prefixes tell you what direction the taking goes:
- ac- (toward) + cept → accept: take something toward yourself, receive it
- con- (together) + cept/ceive → concept / conceive: take ideas and grasp them together in the mind
- re- (back) + ceive → receive: take something back / in
- per- (through) + ceive → perceive: take in through the senses
- de- (down, away) + ceive → deceive: take someone in by leading them astray
- ex- (out) + cept → except: take something out of a group
- anti- (before) + cip → anticipate: take hold of something before it happens
- inter- (between) + cept → intercept: take something between its start and end

Notice the steady logic: the prefix supplies the direction, and cap/cept/ceiv always supplies the act of taking. One quirky member is conceit — the same con- + cept, but the "idea you grasped" turned into "the too-flattering idea you hold of yourself." The family is large, but not perfectly regular.