c. 1600, "act of chewing the cud; act of meditating," from Latin ruminationem (nominative ruminatio) "a chewing the cud," noun of action from past-participle stem of ruminare "to chew the cud," also "turn over in the mind" (see ruminate).
"elastic substance obtained from a tropical American tree, formerly used in the manufacture of chewing-gum," 1877, American English (in chicle-gum), from Mexican Spanish chicle, from Nahuatl (Aztecan) tzictli.
"animal that chews the cud," 1660s, from Latin ruminantem (nominative ruminans), present participle of ruminare "to chew the cud" (see ruminate). As an adjective from 1670s, "ruminating, chewing the cud."
"softened tobacco pressed into flat cakes" for chewing or smoking, 1837, presumably from the surname Cavendish, perhaps the name of a Virginia planter. The name is from the place in Suffolk, literally "Cafa's enclosed pasture," from proper name Cafa or Cafna.
Old English ceowan "to bite, gnaw, chew," from West Germanic *keuwwan (source also of Middle Low German keuwen, Dutch kauwen, Old High German kiuwan, German kauen), perhaps from PIE *gyeu- "to chew" (source also of Old Church Slavonic živo "to chew," Lithuanian žiaunos "jaws," Persian javidan "to chew").
Figurative sense of "to think over" is from late 14c.; to chew the rag "discusss some matter" is from 1885, apparently originally British army slang. Related: Chewed; chewing. To chew (someone) out (1948) probably is military slang from World War II. Chewing-gum is by 1843, American English, originally hardened secretions of the spruce tree.
as an insult, "one who shirks or gives up," by 1878, American English, in reference to race horses, agent noun from quit (v.) in the "stop, cease" sense. It is attested by 1871 as "one who gives up (chewing tobacco)."
gum or resin obtained from certain small trees of the Mediterranean region, late 14c., mastik, from Old French mastic (13c.) and directly from Late Latin mastichum, from Latin mastiche, from Greek mastikhe, a word of uncertain origin, probably related to masasthai "to chew" (see mastication). The substance is used as a chewing gum in the East.