Source : Webster's Revised Unabridged Dictionary (1913)

Cotter \Cot"ter\, Cottar \Cot"tar\ (k?t"t?r), n. [LL. cotarius,
   cottarius, coterius. See {Cot}.]
   A cottager; a cottier. --Burns.

         Through Sandwich Notch the West Wind sang Good morrow
         to the cotter.                           --Whittier.

Cotter \Cot"ter\ (k[o^]t"t[~e]r), n.
   1. 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.

   Note: [See Illust.] In the United States a cotter is commonly
         called a {key}.

   2. A toggle.

Cotter \Cot"ter\, v. t.
   To fasten with a cotter.

Source : WordNet®

cotter
     n 1: a peasant farmer in the Scottish highlands [syn: {cottar}]
     2: a medieval English villein [syn: {cottier}]
     3: fastener consisting of a wedge or pin inserted through a
        slot to hold two other pieces together [syn: {cottar}]