c. 1300, "joyful song," also a kind of dance in a ring, from Old French carole "kind of dance in a ring, round dance accompanied by singers," a word of uncertain origin. Perhaps from Medieval Latin choraula "a dance to the flute," from Latin choraules "flute-player," from Greek khoraules "flute player who accompanies the choral dance," from khoros "chorus" (see chorus) + aulein "to play the flute," from aulos "reed instrument" (see alveolus). OED writes that "a Celtic origin is out of the question." The meaning "Christmas hymn of joy" is attested from c. 1500.
masc. proper name, from Medieval Latin Carolus, which is of Germanic origin, from the common noun meaning "man, husband" (see carl). As a fem. proper name, an abbreviation of Caroline. The masc. name never has been popular in U.S.; the fem. form was common after c. 1900 and was a top-10 name for U.S. girls born 1936-1950.
c. 1300, "to dance in a ring," from Old French caroler, from carole (see carol (n.)). As "to sing with joy or festivity" from late 14c. As "go around from place to place in a group singing Christmas carols" it is from 1879, said to be a revival of an old English custom. Related: Caroled; caroling; caroler.