'Pleurosigma' definitions:
Definition of 'Pleurosigma'
From: GCIDE
- Pleurosigma \Pleu`ro*sig"ma\, n. [NL. See Pleuro-, and Sigma.] (Bot.) A genus of diatoms of elongated elliptical shape, but having the sides slightly curved in the form of a letter S. Pleurosigma angulatum has very fine striations, and is a favorite object for testing the high powers of microscopes. [1913 Webster]