measure of quality of a diamond, c. 1600, from water (n.1), perhaps as a translation of Arabic ma' "water," which also is used in the sense "luster, splendor."

Old English wæterian "moisten, irrigate, supply water to; lead (cattle) to water;" from water (n.1). Meaning "to dilute" is attested from late 14c.; now usually as water down (1850). To make water "urinate" is recorded from early 15c. Related: Watered; watering.

Old English wæter, from Proto-Germanic *watr- (source also of Old Saxon watar, Old Frisian wetir, Dutch water, Old High German wazzar, German Wasser, Old Norse vatn, Gothic wato "water"), from PIE *wod-or, suffixed form of root *wed- (1) "water; wet."

To keep (one's) head above water in the figurative sense is recorded from 1742. Water cooler is recorded from 1846; water polo from 1884; water torture from 1928. Linguists believe PIE had two root words for water: *ap- and *wed-. The first (preserved in Sanskrit apah as well as Punjab and julep) was "animate," referring to water as a living force; the latter referred to it as an inanimate substance. The same probably was true of fire (n.).

c. 1400, from water (n.1) + wheel (n.).

type of snake in the U.S. South, 1821, from water (n.1) + moccasin (q.v.).

1540s, from water (n.1) + lily (n.).

"privy with a waste-pipe and means to carry off the discharge by a flush of water," 1755, from water (n.1) + closet (n.).

1931, from water (n.1) + ski (n.). As a verb from 1953.

"level of saturated ground," 1879, from water (n.1) + table (n.).

"sugared water, flavored and frozen," 1818, from water (n.1) + ice (n.).