Old English cros (mid-10c.), from Old Irish cros, probably via Scandinavian, from Latin crux (accusative crucem, genitive crucis) "stake, cross" on which criminals were impaled or hanged, hence, figuratively, "torture, trouble, misery;" originally a tall, round pole; possibly of Phoenician origin. Replaced Old English rood. Also from Latin crux are Italian croce, French croix, Spanish and Portuguese cruz, Dutch kruis, German Kreuz.
"ill-tempered," 1630s, probably from 16c. sense of "contrary, athwart," especially with reference to winds and sailing ships, from cross (n.). Cross-purposes "contradictory intentions" is from 1660s.
c.1200, "make the sign of a cross," from cross (n.). Sense of "to go across" is from c.1400; that of "to cancel by drawing lines over" is from mid-15c. Related: Crossed; crossing.