beard：

n. （下巴上的）胡须He has decided to grow a beard.

他已经决定留起络腮胡子。

He's had his beard shaved off.

他把胡子刮掉了。

moustache：

n. 上唇上的小胡子His full and very thick moustache covers his upper lip.

他又浓又厚的小胡子覆盖了他的上唇。