Source : Webster's Revised Unabridged Dictionary (1913)

Cop \Cop\ (k[o^]p), n. [AS. cop; cf. G. kopf head. Cf. {Cup},
   {Cob}.]
   1. The top of a thing; the head; a crest. [Obs.]

            Cop they used to call The tops of many hills.
                                                  --Drayton.

   2. A conical or conical-ended mass of coiled thread, yarn, or
      roving, wound upon a spindle, etc.

   3. A tube or quill upon which silk is wound.

   4. (Mil. Arch.) Same as {Merlon}.

   5. A policeman. [Slang]

   {Cop waste}, a kind of cotton waste, composed chiefly of
      remnants of cops from which the greater part of the yarn
      has been unwound.