Noun
The first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger. It is usually the most dextrous and sensitive finger of the hand, though not the longest – it is shorter than the middle finger, and may be shorter or longer than the ring finger.
Index finger literally means “pointing finger”, from the same Latin source as indicate; its anatomical names are either “index finger” or “second digit”. (wikipedia.org)
Syn: forefinger, pointer finger, trigger finger, digitus secundus, digitus II, pointer
Word origin: Finger – Old English fingor, from Proto-Germanic *fingraz; perhaps connected with PIE *penkwe-, the root meaning “five.”
Index – “the forefinger,” from Latin index (genitive indicis) “forefinger, pointer, sign, list,” literally “anything which points out,” from indicare “point out”