"baby's bed," usually mounted on rockers or suspended for rocking or swinging, c. 1200, cradel, from Old English cradol "little bed, cot," from Proto-Germanic *kradulaz "basket" (source also of Old High German kratto, krezzo "basket," German Krätze "basket carried on the back").
Figurative sense of "the place where any person or thing is nurtured in the early stages of existence" is from 1580s. The word also was used from late 14c. in reference to various mechanical devices for holding or hoisting. As "frame of wood with long, curved teeth and a scythe blade for cutting grain and laying it in a straight swath," 1570s. As "rest on a telephone for the receiver when not in use" is from 1903.
The children's game of cat's-cradle is so called by 1768. Cradle-snatching "amorous pursuit of younger person" is from 1906.
"It's like cradle-snatching to want to marry a girl of sixteen, and you ought to be ashamed of yourself, for you can't be much more than twenty one yourself." ["Edith Van Dyne" (L. Frank Baum), "Aunt Jane's Nieces Abroad," 1906]
c. 1400, "place or rock in or as in a cradle," from cradle (n.). From 1750 as "cut (grain) with a cradle." By 1944 as "hang up a telephone receiver." Related: Cradled; cradling.
c. 1200, "two-wheeled vehicle," usually for one horse and often without springs, from Old Norse kartr or a similar Scandinavian source, akin to and replacing Old English cræt "cart, wagon, chariot," perhaps originally "body of a cart made of wickerwork, hamper" and related to Middle Dutch cratte "woven mat, hamper," Dutch krat "basket," Old English cradol (see cradle (n.)).
Many old allusions are from the cart being used to convey offenders to the gallows (and sometimes serving as a drop for hangings) or for public exposure, especially of lewd women, either in the cart or tied to its tail. Compare tumbrel. To put the cart before the horse in a figurative sense "reverse the natural or proper order of things" is from 1510s in those words; the image in other words dates to mid-14c.: put the plow (sull) before the oxen.
Transitive meaning "move (something) back and forth or up and down" is from c. 1300; of dogs and their tails from mid-15c.: "and whanne they [hounds] see the hure maystre they wol make him cheere and wagge hur tayles upon him." [Edward, Duke of York, "The Master of Game," 1456]. Related: Wagged; wagging. Wag-at-the-wall (1825) was an old name for a hanging clock with pendulum and weights exposed.
[to sway, move backward and forward] Middle English rokken "rock (a cradle), cause to sway back and forth; rock (someone) in a cradle," from late Old English roccian "move a child gently to and fro" in a cradle, which is related to Old Norse rykkja "to pull, tear, move," Swedish rycka "to pull, pluck," Middle Dutch rucken, Old High German rucchan, German rücken "to move jerkily."
The earliest associations of the word were with slumber, rest, security. The sense of of "sway to and fro under some impact or stress" is from late 14c., especially of vessels in the waves (1510s); hence rock the boat in the figurative sense "stir up trouble" (1914). The sense of "swing to and fro in or as in a rocking chair" is by 1795.