1550s, "from or found in the regions near the poles of the Earth," from Middle French polaire (16c.) or directly from Medieval Latin polaris "of or pertaining to the poles," from Latin polus "an end of an axis" (see pole (n.2)). By 1816 as "of or pertaining to a pole or poles of a sphere." Meaning "directly opposite in character or tendency" is attested from 1832. Polar bear is attested from 1781.