An optical device for obtaining interference fringes

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Biprism \Bi"prism\, n. [Pref. bi- + prism.] A prism whose refracting angle is very nearly 180 degrees. A combination of two short rectangular glass prisms cemented together at their diagonal faces so as to form a cube; -- called also optical cube . It is ...

Wiktionary Word definitions in Wiktionary
n. 1 (context mathematics English) A fusion of two triangular prisms 2 (context physics English) An optical device of this construction used to generate interference fringes

WordNet Word definitions in WordNet
n. an optical device for obtaining interference fringes