"action in resistance or response to another action or power," 1640s, from re- "back, again, anew" + action (q.v.). Modeled on French réaction, older Italian reattione, from Medieval Latin reactionem (nominative reactio), a noun of action formed in Late Latin from the past-participle stem of Latin reagere "react," from re- "back" + agere "to do, perform."

Originally a word in physics and dynamics. In chemistry, "mutual or reciprocal action of chemical agents upon each other," by 1836. The general sense of "action or feeling in response" (to a statement, event, etc.) is recorded from 1914. Reaction time, "time elapsing between the action of an external stimulus and the giving of a signal in reply," attested by 1874.

1811, "a book printed by William Caxton (obit c. 1491), English merchant in the Netherlands who learned there the art of printing and introduced it to England. The surname is from the place in Cambridgeshire, literally "Kak's estate," from the Old Norse personal name Kakkr.

"gourmand," 1650s, from Greek deipnosophistes "one learned in the mysteries of the kitchen," from deipnon "chief meal, dinner" (which is of unknown origin) + sophistes "master of a craft" (see sophist). the word has come down thanks to "Deipnosophistai," 2c. B.C.E. work on gastronomy by Athenaeus.

"gift of tongues, speaking in tongues, ability to speak foreign languages without having learned them," 1857 (earlier in German and Italian), from Greek glōssa "tongue, language" (see gloss (n.2)) + lalia "talk, prattle, a speaking," from lalein "to speak, prattle," echoic.

call-and-response exclamation in singing, by 1933, associated with U.S. bandleader Cabell "Cab" Calloway (1907-1994) and especially his signature song "Minnie the Moocher," which dates from 1931.

Calloway recalled in his autobiography that the song came first and the chorus was later improvised when he forgot the lyrics during a radio broadcast. ["Harlem Renaissance Lives," Oxford, 2009]

1590s, "pertaining to the clergy," from cleric + -al (1), or from French clérical, from Old French clerigal "learned," from Latin clericalis, from clericus (see cleric). Meaning "pertaining to clerks and copyists" is from 1798.

Clericalism "sacerdotalism, power or influence of the clergy" is from 1849. Clericality "quality of being clerical" is from 1650s.