latch v.

1560s, in mathematics, from Greek lemma (plural lemmata) "something received or taken; an argument; something taken for granted," from root of lambanein "to take," from PIE root *(s)lagw- "to seize, take" (source also of Sanskrit labhate, rabhate "seizes;" Old English læccan "to seize, grasp;" Greek lazomai "I take, grasp;" Old Church Slavonic leca "to catch, snare;" Lithuanian lobis "possession, riches"). Related: Lemmatical.

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"), 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"). A doublet of chase (v.).

Its senses in early Middle English also included "to chase, hunt," which later went with chase (v.). Of sleep, etc., from early 14c.; of infections from 1540s; of fire from 1734 (compare Greek aptō "fasten, join, attach, grasp, touch," also "light, kindle, set on fire, catch on fire"). Related: Catched (obsolete); catching; caught.

The meaning "act as a catcher in baseball" is recorded from 1865. To catch on "apprehend, understand" is by 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).