Cop /(kŏp)/

Cop

n.
  1. The top of a thing; the head; a crest. [Obs.]
    Cop they used to call The tops of many hills.
  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. Same as Merlon. (Mil. Arch.)
  5. A policeman. [Slang]

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