noun
a lens made of optical crown glass
• Hypernyms: ↑lens, ↑lense, ↑lens system
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noun : the crown glass component of an achromatic lens
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Optics.
a lens made of crown glass, usually used as the converging lens component of an achromatic lens.
[1825-35]
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crown lens,
the convex part of an achromatic lens, made of crown glass.
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n. a lens made of crown glass and usu. forming one component of an achromatic lens
Useful english dictionary. 2012.