The Collaborative International Dictionary
Amphidisc
Amphidisc \Am"phi*disc\, n. [Gr. 'amfi` + di`skos a round plate.] (Zo["o]l.) A peculiar small siliceous spicule having a denticulated wheel at each end; -- found in freshwater sponges.
Wiktionary
amphidisc
n. (context zoology English) A small siliceous spicule having a denticulate wheel at each end, found in freshwater sponges.