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 capere "to take, hold," from PIE root *kap- "to grasp."
Its senses in early Middle English also included "chase, hunt," which later went with chase (v.). Of sleep, etc., from early 14c.; of infections from 1540s; of fire from 1734 (compare Greek apto "fasten, grasp, touch," also "light, kindle, set on fire, catch on fire"). Related: Catched (obsolete); catching; caught.
Meaning "act as a catcher in baseball" recorded from 1865. To catch on "apprehend, understand" is 1884, American English colloquial. To catch the eye "draw the attention" is attested by 1718. Catch as catch can has roots in late 14c. (cacche who that cacche might).
1520s, "manner or style of expression," also "brief expression with some unity; two or more words expressing what is practically a single notion," from Late Latin phrasis "diction," from Greek phrasis "speech, way of speaking, enunciation, phraseology," from phrazein "to tell, declare, indicate, point out, show, inform," also passively (phrazomai), "indicate to oneself, think or muse upon, consider; think up, contrive; suppose, believe, imagine; perceive, observe."
The Greek verb is of uncertain origin; perhaps it is connected with phrenes "wits, senses, sanity," phrēn "the mind, the heart," literally "midriff, diaphragm" (see phreno-). The musical sense of "a short and somewhat independent passage from a piece" is from 1789. Phrase-book "collection of expressions peculiar to a language" is by 1590s.