1591, "to turn a ship on its side" (with the keel exposed), from M.Fr. carene
"keel," from It. (Genoese dialect) carena,
from L. carina
"keel of a ship," originally "nutshell." Generalized sense of "to lean, to tilt" is 1883; confused with career
(v.) since at least 1923. To career
is to move rapidly; to careen
is to lurch from side to side (often while moving rapidly).