(1):

(n.) A toggle.

(2):

(v. t.) To fasten with a cotter.

(3):

(n.) Alt. of Cottar

(4):

(n.) A piece of wood or metal, commonly wedge-shaped, used for fastening together parts of a machine or structure. It is driven into an opening through one or all of the parts. [See Illust.] In the United States a cotter is commonly called a key.