White·head (hwīt'hěd', wīt'-) British mathematician and philosopher. A founder of mathematical logic, he wrote Principia Mathematica (1910-1913) with Bertrand Russell and Process and Reality (1929).
A tiny epidermal cystlike mass with a narrow or obstructed opening on the skin surface, which may rupture, caused by the retention of secretions of a sebaceous gland. Also called closed comedo.