The Collaborative International Dictionary of English v.0.48:

Millepore \Mil"le*pore\ (m[i^]l"l[-e]*p[=o]r), n. [L. mille
   thousand + porus pore: cf. F. mill['e]pore.] (Zool.)
   Any coral of the genus Millepora, having the surface nearly
   smooth, and perforated with very minute unequal pores, or
   cells. The animals are hydroids, not Anthozoa. See
   Hydrocorallia.
   [1913 Webster]