- a small, black-tipped, fatty mass in a skin follicle, especially of the face; comedo.
- any of several birds having a head that is black, as the greater scaup, Aythya marila.
- a malignant, infectious disease of turkeys, chickens, and many wild birds, caused by a protozoan parasite, Histomonas meleagridas, attacking especially the intestines and liver, and often characterized by a darkening of the skin on the head.
- a black-tipped plug of fatty matter clogging a pore of the skin, esp the duct of a sebaceous gland
- an infectious and often fatal disease of turkeys and some other fowl caused by the parasitic protozoa Histomonas meleagridis
- any of various birds, esp gulls or ducks, with black plumage on the head
