Term: optical crown: optical glass of low dispersion and low refractive index
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: chilblain: inflammation of the hands and feet caused by exposure to cold and moisture
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: afterpiece: a brief dramatic piece (usually comic) presented after a play
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: nuclear terrorism: the use of a nuclear device by a terrorist organization to cause massive devastation or the use (or threat of use) of fissionable radioactive materials
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: classroom project: a school task requiring considerable effort
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: isometry: a one-to-one mapping of one metric space into another metric space that preserves the distances between each pair of points
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: sheet: bed linen consisting of a large rectangular piece of cotton or linen cloth; used in pairs
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: podocarpaceae: gymnosperms with simple persistent needlelike or scalelike leaves
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: osteostraci: extinct group of armored fish-like vertebrates; taxonomy is not clear
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: areolar tissue: fibrous connective tissue with the fibers arranged in a mesh or net
Broader: optical glass: clear homogeneous glass of known refractive index; used to make lenses | Unrelated: gemination: the doubling of a word or phrase (as for rhetorical effect)