a small, whitish nodule of the skin, somewhat like a millet seed, resulting from retention of the secretion of a sebaceous gland
See milium in American Heritage Dictionary 4
(mĭlˈē-əm)
nounpl.mil·i·a(-ē-ə)
A small, white or yellowish cystlike mass just below the surface of the skin, caused by retention of the secretion of a sebaceous gland. Also called whitehead.