Uses
A lone index finger held vertically is often used to represent the number 1, or when held up or moved side to side (finger-wagging), it can be an admonitory gesture. With the hand held palm out and the thumb and middle fingers touching, it represents the letter d in the American Sign Language alphabet. In sports, it can also represent victory, as some championship-winning teams raise their index finger (often saying "We're number one!") while posing for a championship team photo – oversized foam hands with a single upraised index are also used for this purpose; compare with the victory sign. For the vast majority of computer users, it is the finger most often used to click a mouse, as well as the finger used in the untrained 'hunt and peck' Typing style.
Read more about this topic: Index Finger