The ring finger is the fourth digit of the human hand, and the second most ulnarfinger, 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. 
The medical finger. Some cultures named it after its supposed magic power, especially the healing power. An example of the idea of its healing power is Bhaisajyaguru, the Medicine Buddha, who uses his right ring finger for medicine.
English: leech finger
German: Arztfinger (doctor's finger)
Japanese: kusuri-yubi (medicine finger)
Japanese: kusushi-yubi (doctor's finger)
Korean: yak-ji (medicine finger)
Latin: digitus medicinalis (medical finger)
The ring finger. Some cultures associated it to magic rings. This is particularly common in European languages.
Albanian: gishti i unazës (ring finger)
Cornish: bys-bysow (ring finger)
Croatian: prstenjak (ring finger)
Czech: prsteníček (ring finger)
Danish: ringfinger (ring finger)
Dutch: ringvinger (ring finger)
English: ring finger
French: annulaire (ring finger)
German: Ringfinger (ring finger)
Hungarian: gyűrűsujj (ring finger)
Icelandic: baugfingur (ring finger)
Italian: dito anulare (ring finger)
Latin: digitus annularis (ring finger)
Latvian: zeltnesis (gold carrier)
Malay: jari manis (sweet finger)
Norwegian: ring(e)finger (ring finger)
Persian:'انگشت انگشتری' (ring finger)
Polish: palec serdeczny (lit. cordial finger, etymology is from "heart" - in Polish "serce" which means "heart", because it's rather "finger of heart") (ring finger)
Portuguese: dedo anelar (ring finger)
Romanian: degetul inelar (ring finger)
Slovak: prstenník (ring finger)
Spanish: dedo anular (ring finger)
Swahili: cha pete (of the ring)
Swedish: ringfinger (ring finger)
Tamil: Mothira Viral (ring finger)
Turkish: Yüzük parmağı (ring finger)
The nameless finger. Many cultures avoided the true name of a powerful entity, and called it indirectly or called it nameless.
Bulgarian: безименен пръст (nameless finger)
Cantonese: 無名指 mo ming ji (nameless finger)
Finnish: nimetön (sormi) (nameless finger)
Japanese: nanashi-yubi (nameless finger)
Lithuanian: bevardis (nameless)
Mandarin: 无名指 wúmíngzhǐ (nameless finger)
Persian: binàme (nameless)
Russian: bezymyannyi palets (nameless finger)
Sanskrit: anámika (nameless)
Tatar: atsyz parmak (nameless finger)
In other languages this finger takes its name from its place between the other fingers.
Latin: digitus medio proximus (the finger next to the middle)
Greek: paramesosπαράμεσος (para = next to + mesos = in the middle: the finger next to the middle finger)
Serbian: domali prst (the finger next to the little)
The wedding ring
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Main article: wedding ring
In Western cultures a wedding ring is traditionally worn on the ring finger. According to tradition in some countries, 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 believed to be directly connected to the heart, a symbol of love.
In medieval Europe, the Christian wedding ceremony placed the ring in sequence on the index, middle, and ring fingers of the left hand, representing the trinity — God the Father, God the Son, and God the Holy Spirit. 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 Norway, Russia, Bulgaria, Poland, Germany, Austria, Denmark, some countries of former Yugoslavia and in Spain (except in Catalonia) the wedding ring is worn on the ring finger on the right hand.
In the Jewish wedding ceremony, the groom places the ring on the bride's index finger, and not ring finger; the ring is usually moved to the ring finger after the ceremony.
In the Indian tradition, the right hand is considered as auspicious. Hence the wedding ring is worn on the right hand. However, despite tradition, some wear the ring on the left hand, matching cultural practice
in some western countries.