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.).
Old English hweol, hweogol "wheel," from Proto-Germanic *hwewlaz (source also of Old Norse hvel, Old Swedish hiughl, Old Frisian hwel, Middle Dutch weel), from PIE *kw(e)-kwl-o- "wheel, circle," suffixed, reduplicated form of root *kwel- (1) "revolve, move round; sojourn, dwell."
Figurative sense is early 14c. Wheel of fortune attested from early 15c. Slang wheels "a car" is recorded from 1959. Wheeler-dealer is from 1954, a rhyming elaboration of dealer.