Bi"prism (?), n. [Pref. bi- + prism.] 1. A prism whose refracting angle is very nearly 180 degrees.

2. 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 used in one form of photometer.

Bi"prism (?), n. [Pref. bi- + prism.] 1. A prism whose refracting angle is very nearly 180 degrees.

2. 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 used in one form of photometer.