The ring finger is the fourth proximal digit of the human hand, and the second most ulnar finger, located between the middle finger and the little finger. It is also called digitus medicinalis, the fourth finger, digitus annularis, digitus quartus, or digitus IV in anatomy.

According to László A. Magyar, the names of the ring finger in many languages reflect an ancient belief that it is a magical finger. It is named after magic or rings, or called nameless (for example, in Chinese: 無名指, unnamed finger). In Sanskrit and other Indic languages, the name for the ring finger is Anamika ("nameless").^{[citation needed]}

In Western cultures, a wedding ring is traditionally worn on the ring finger. This developed from the Roman "annulus pronubis" when the man gave a ring to the woman at the betrothal ceremony. According to tradition in some countries (derived from Roman belief), the wedding ring is worn on the left ring finger because the vein in the left ring finger, referred to as the vena amoris, was said to be directly connected to the heart, a symbol of love. Blessing the wedding ring and putting it on the bride's finger dates from the 11th century. In medieval Europe, the Christian wedding ceremony placed the ring in sequence on the index, middle, and ring fingers of the left hand. The ring was then left on the ring finger. In a few European countries, the ring is worn on the left hand prior to marriage, then transferred to the right during the ceremony. For example, a Greek Orthodox bride wears the ring on the left hand prior to the ceremony, then moves it to the right hand after the wedding. In England, the 1549 Prayer Book declared "the ring shall be placed on the left hand". By the 17th and 18th centuries the ring could be found on any finger after the ceremony — even on the thumb.