Definition of blackhead
1 : a small plug of darkened sebum and dead skin cells that fills a pore of the skin especially on the face
— called also comedo, open comedo— compare whitehead
2 : a destructive disease of turkeys and related birds caused by a protozoan (Histomonas meleagridis) that invades the intestinal ceca and liver
3 : a larval clam or mussel attached to the skin or gills of a freshwater fish
Love words? Need even more definitions?Merriam-Webster unabridged
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