optical glass

English Thesaurus

1. clear homogeneous glass of known refractive index; used to make lenses (noun.substance)

hypernym	:	glass,
definition	:	a brittle transparent solid with irregular atomic structure (noun.substance)

hyponym	:	crown glass, optical crown, optical crown glass,
definition	:	optical glass of low dispersion and low refractive index (noun.substance)

hyponym	:	flint glass, optical flint,
definition	:	optical glass of high dispersion and high refractive index (noun.substance)