Biprism
Pronunciation : Bi"prism
Part of Speech : n.
Definition : 1.
Defn: 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.
[Pref. bi- + prism.]
Source : Webster's Unabridged Dictionary, 1913