'Planorbis' definitions:

Definition of 'Planorbis'

From: GCIDE

Planorbis \Pla*nor"bis\, n. [NL., fr. L. planus flat + orbis a circle.] (Zool.) Any fresh-water air-breathing mollusk belonging to Planorbis and other allied genera, having shells of a discoidal form. [1913 Webster]