late 14c., "middle point of a circle; point round which something revolves," from Old French centre (14c.), from Latin centrum "center," originally fixed point of the two points of a drafting compass, from Greek kentron "sharp point, goad, sting of a wasp," from kentein "stitch," from PIE root *kent- "to prick" (cf. Breton kentr "a spur," Welsh cethr "nail," Old High German hantag "sharp, pointed").
Figuratively from 1680s. Meaning "the middle of anything" attested from 1590s. Spelling with -re popularized in Britain by Johnson's dictionary (following Bailey's), though -er is older and was used by Shakespeare, Milton, and Pope. Center of gravity is recorded from 1650s. Center of attention is from 1868.