blackhead

noun3

1. •
   A type of comedo, a skin blemish, a type of acne vulgaris, where a pore becomes clogged with a dark, hard, cheesy keratin-filled substance forming a hard black "head" on the skin's surface.

   • See there! A son is born And we pronounce him fit to fight There are blackheads on his shoulders And he pees himself in the night. — 1972
2. •
   A scaup: any of various ducks of the genus Aythya.
3. •
   A form of histomoniasis in poultry, characterized by cyanotic discoloration on the bird's head.