Hierarchy:
Description:
{{optics}} A disk of high-quality quartz glass having at least one side ground and polished with a deviation in flatness less than 50 nanometers all over, and a surface quality of 5 microfinish or less; used, in an interferometer, to measure the flatness of other surfaces.
Ngram:
Ngram Text:
optical flat
Source:
Wiktionary
Issue:
0
Wiktionary tag:
Ngram Count:
2