Head

From Brickipedia, the LEGO Wiki.

A LEGO head is a cylindrical piece that sits on top of a minifigure and serves as it's head. It has at least two eyes and a mouth printed on, but no nose. They also can have stuff like beard, bangs, lips for girls, and eyeglasses. There are two colors, the classic yellow and the newer, more realistic, natural skin tone color. Skeletal heads are white and have a skull design on them.

There are also different shaped heads, such as Star Wars' Yoda, and Harry Potter's house elves and goblins. There are also the Star Wars Wookie, Ewok, and Gammorean Guard heads, which have parts that come over the torso to add texture.