Cognition is the use of mental processes such as learning, remembering, thinking, and understanding. It stems from the Latin verb cognoscere, meaning “become acquainted with.” Not every word with the letter string “c-o-g” is related, but quite a few are. Details about cognition’s cognates follow.
But first, a look at the construction of the words. The syllable cog isn’t the basis of terms related to knowing and thinking; cognoscere consists of co- and gnoscere; that word means “come to know.” Know itself is cognate with gnoscere and the Greek verb gignōskein—the basis of gnome, best known as the name of a subterranean dwarflike creature in folklore but also a synonym for maxim, and gnosis, a word referring to spiritual knowledge that is also the root of prognosis (literally, “foreknowledge”) and diagnosis, meaning “identification” or “analysis.”
Cognate itself is not cognate with cognition: It means “related,” and stems from the Latin word nasci, meaning “to be born,” and is cognate with nascent (and native). Nor is cognomen, which means “nickname” or “additional name” and derives from the Latin noun nomen, meaning “name.”
Interestingly, cogent, meaning “necessary” or “urgent,” and especially its cognate cogitation, which means “intent thought,” are also unrelated to cognition; they derive respectively from the Latin verb agere, meaning “drive,” and its frequentative (repeated or recurrent) form agitare, which is also the origin of agitate. Another word with a distinct etymology is cog, referring to a tooth on a wheel in a gear mechanism and probably borrowed from a Scandinavian language.
Words in the cognoscere family in English include recognition (literally, “knowing again”) and precognition (literally, “knowing before”); the latter was the unusual ability of the Precogs in Steven Spielberg’s film Minority Report and the Philip K. Dick short story on which it is (loosely) based. Two other words that are related— unexpectedly so—are reconnaissance (“military survey”) and that word’s verb form, reconnoiter, both adopted from French but ultimately stemming from recognoscere, the Latin origin of recognize.
Other relatives are cognizance (“awareness,” “acknowledgment,” or “responsibility”) and recognizance, derived from an earlier sense of reconnaissance (“acknowledgment”) and used in legal contexts in phrases such as “released on his own recognizance” to indicate that someone recognizes his obligation to appear in court at a later date.
Connoisseur (“expert”), from French, and its Italian cousin cognoscente (which in English developed a separate sense of “someone in the know”) are also related, as are incognito (“unknown,” from Italian and referring to being in disguise or anonymous or using a false name) and “terra incognita” (literally, “unknown land”), taken directly from Latin.