mil·le·pore (mĭl'ə-pôr', -pōr') n. Any of various reef-building hydrocorals of the order Milleporina of tropical marine waters, forming white or yellowish calcareous structures and resembling the true corals of the class Anthozoa.
[Italian millepora : mille, thousand (from Latin mīlle, thousand; see gheslo- in Indo-European roots) + -pora (alteration of poro, tufa, pore; see madrepore).]