Ger. Rücken). Many I.E. languages show signs of once having distinguished the horizontal back of an animal (or a mountain range) from the upright back of a human. In other cases, a modern word for "back" may come from a word related to "spine" (It. schiena, Rus. spina) or "shoulder, shoulder blade" (Sp. espalda, Pol. plecy).
late 15c., "to move (something) back," from back
(adj.); meaning "to support" (as by a bet) is first attested 1540s.
O.E. bæc "backwards, behind" (see back
(n.)). Back-seat driver first attested 1926. The back of (one's) hand has been used to imply contempt and rejection since at least 1300; to know (something) like the back of one's hand, implying familiarity, is first attested 1943.
To be on the back burner in the figurative sense is from 1960, from the image of a cook keeping a pot there to simmer while he or she works on another concoction at the front of the stove. Back-to-nature (adj.) is first attested 1915.