n. (Paleon.) A fossil coral of the family Cyathophyllidæ; sometimes extended to fossil corals of other related families belonging to the group Rugosa; -- also called cup corals. Thay are found in paleozoic rocks. [ 1913 Webster ]

a. [ NL. cyathophyllum, fr. Gr. ky`aqos a cup + fy`llon a leaf. ] (Paleon.) Like, or pertaining to, the family Cyathophyllidæ. [ 1913 Webster ]