Blackheads are small, dark spots on someone's skin caused by blocked pores.
blackhead in British English
(ˈblækˌhɛd)
noun
1.
a black-tipped plug of fatty matter clogging a pore of the skin, esp the duct of a sebaceous gland
Technical name: comedo
2.
an infectious and often fatal disease of turkeys and some other fowl caused by the parasitic protozoa Histomonas meleagridis
Technical name: infectious enterohepatitis
3.
any of various birds, esp gulls or ducks, with black plumage on the head
blackhead in American English
(ˈblækˌhɛd)
noun
1.
any of various black-headed birds, esp. the scaup duck
2.
a black-tipped plug of dried fatty matter in a pore of the skin
3. US
an infectious disease of the intestines and liver of turkeys, chickens, etc. caused by a protozoan (Histomonas meleagridis) and characterized by a dark, discolored comb
4.
the parasitic larva of a freshwater mussel (family Unionidae) encysted in the gills, etc. of a fish