also *gweie-, Proto-Indo-European root meaning "to live."

It forms all or part of: abiogenesis; aerobic; amphibian; anaerobic; azo-; azoic; azotemia; bio-; biography; biology; biome; bionics; biopsy; biota; biotic; cenobite; Cenozoic; convivial; couch-grass; epizoic; epizoon; epizootic; macrobiotic; Mesozoic; microbe; Protozoa; protozoic; quick; quicken; quicksand; quicksilver; quiver (v.) "to tremble;" revive; survive; symbiosis; viable; viand; viper; vita; vital; vitamin; victuals; viva; vivace; vivacious; vivarium; vivid; vivify; viviparous; vivisection; whiskey; wyvern; zodiac; Zoe; zoetrope; zoic; zoo-; zoolatry; zoology; zoon; zoophilia; zoophobia; zooplankton.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit jivah "alive, living;" Old Persian *jivaka- "alive," Middle Persian zhiwak "alive;" Greek bios "one's life, course or way of living, lifetime," zoe "animal life, organic life;" Old English cwic, cwicu "living, alive;" Latin vivus "living, alive," vita "life;" Old Church Slavonic zivo "to live;" Lithuanian gyvas "living, alive," gyvata "(eternal) life;" Old Irish bethu "life," bith "age;" Welsh byd "world."

"movable, very loose sand bank in a sea, lake, or river," capable of swallowing heavy objects and sometimes dangerous to vessels or travelers," c. 1300, from Middle English quyk "living" (see quick (adj.)) + sond "sand" (see sand (n.)). Figurative use by 1590s. Old English had cwecesund, but this might have meant "lively strait of water."

in couch-grass, 1570s; a corruption of Old English cwice "living, alive" (see quick (adj.)).

Old English cwic-beam, a name of some tree, from beam (n.), in its original sense of "tree," apparently with quick (adj.), though "the precise force of the adj. is not clear" [OED]. The aspen, old world mountain ash, and rowan have been proposed as the tree in question.

c. 1300, quikenen, "come to life, receive life," also transitive, "give life to," also "return to life from the dead;" see quick (adj.) + -en (1). The earlier verb was simply quick (c. 1200, from late Old English gecwician, and compare Old Norse kvikna).

The sense of "hasten, accelerate, impart speed to" is from 1620s. The intransitive meaning "become faster or more active" is by 1805. Also, of a woman, "enter that state of pregnancy in which the child gives indications of life;" of a child, "begin to manifest signs of life in the womb" (usually about the 18th week of pregnancy); probably originally in reference to the child but reversed and also used of the mother. Related: Quickened; quickening.

"anything made or done quickly," 1940, from quick (adj.) + -ie. As "alcoholic drink meant to be taken hurriedly," by 1941 (quick one in this sense from 1928). From 1926 as "motion picture made in a short time." By 1975 as "sex act done hastily."

"caustic lime, lime not yet slaked with water," late 14c., from quick (adj.) "living" + lime (n.1). A loan-translation of Latin calx viva. So called perhaps for being unquenched, or for the vigorousness of its qualities; compare Old English cwicfyr "sulfur."

mid-15c., quickli, "lively, vivid, lifelike," from quick (adj.) + -ly (2), and compare late Old English cwiculice "vigorously, keenly." Meaning "rapidly, in a short space of time" is from c. 1200.

"a quick-step, a march in quick time," 1752, from quick (adj.) + march (n.1).

c. 1200, quiknesse, "state of being alive," from quick (adj.) + -ness. Early 15c. as "alacrity, speed, rapidity;" mid-15c. as "readiness of perception, keenness of mind."