ring finger

noun

Etymology: From Middle English ring fynger. So named from the wearing of wedding rings on this finger, originating from medieval belief that a nerve or artery ran from it to the heart.

1. The finger between the middle finger and the little finger; the "third finger" (UK) or the "fourth finger" (US), especially of the left hand. (The ring finger is the left hand; a ring finger is either hand.)

   “See Thesaurus:ring finger”