Why is the ninth month called September?
c.1200, "to take, capture," from Anglo-French or Old North French cachier "catch, capture" (animals) (Old French chacier "hunt, pursue, drive (animals)," Modern French chasser "to hunt;" making it a doublet of chase (v.)), from Vulgar Latin *captiare "try to seize, chase" (also source of Spanish cazar, Italian cacciare), from Latin captare "to take, hold," frequentative of Latin capere "to take, hold" (see capable).
Senses in early Middle English also included "chase, hunt," which later went with chase (v.). Of infections from 1540s; of fire from 1734; of sleep, etc., from early 14c. Related: Catched (obsolete); catching; caught.
Meaning "act as a catcher in baseball" recorded from 1865. To catch on "apprehend" is 1884, American English colloquial. To catch (someone's) eye is first attested 1813, in Jane Austen. Catch as catch can first attested late 14c.
late 14c., "device to hold a latch of a door," also "a trap;" also "a fishing vessel," from catch (v.). Meaning "action of catching" attested from 1570s. Meaning "that which is caught or worth catching" (later especially of spouses) is from 1590s. Sense of "hidden cost, qualification, etc." is slang first recorded 1855 in P.T. Barnum.