A lock of hair hanging at the side of the face or head; a similar part of a wig. Now chiefly: specifically (in plural) long locks of hair hanging down in front of the ears, worn by Hasidic and Orthodox Yemenite male Jews; = "payess".

A canal lock or airlock situated at the side.

A firearm in which the lock is to the side of the action. Frequently attributive, designating a firearm of this type.