1690s, "curved line, a continuous bending without angles," from curve (v.). With reference to the female figure (usually plural, curves), from 1862; in reference to statistical graphs, by 1854; as a type of baseball pitch that does not move in a straight line, from 1879. An old name for it was slow. "Slows are balls simply tossed to the bat with a line of delivery so curved as to make them almost drop on the home base." [Chadwick's Base Ball Manual, 1874]
early 15c. (implied in curved), intransitive, "have or assume a curved form," from Latin curvus "crooked, curved, bent," and curvare "to bend," both from PIE root *sker- (2) "to turn, bend." Transitive sense of "cause to take the shape of a curve, bend" is from 1660s.
"state of being curved," 1540s, from Late Latin curvitatem (nominative curvitas), noun of state from past-participle stem of curvare "to bend, curve" (see curve (v.)).
1793, cauvaut, "to prance, bustle nimbly or eagerly," American English, of uncertain origin, sometimes said to be an alteration of curvet "a leap by a horse," a word from French that is related to curve (v.). Or perhaps from ca-, ka-, colloquial intensive prefix + vault (v.) "to jump, leap." Modern form attested by 1829. Related: Cavorted; cavorting.
also *ker-, Proto-Indo-European root meaning "to turn, bend."
It forms all or part of: arrange; circa; circadian; circle; circuit; circum-; circumcision; circumflex; circumnavigate; circumscribe; circumspect; circumstance; circus; cirque; corona; crepe; crest; crinoline; crisp; crown; curb; curvature; curve; derange; flounce (n.) "deep ruffle on the skirt of a dress;" krone; ring (n.1) "circular band;" ranch; range; ranger; rank (n.) "row, line series;" research; recherche; ridge; rink; rucksack; search; shrink.
It is the hypothetical source of/evidence for its existence is provided by: Latin curvus "bent, curved," crispus "curly;" Old Church Slavonic kragu "circle;" perhaps Greek kirkos "ring," koronos "curved;" Old English hring "ring, small circlet."