411 REFERENCE · Wiktionary
Porro prism
Reference material by Wiktionary contributors. This retains its source identity and is not 411 news reporting.
English
Etymology
Named after its inventor, Ignazio Porro.
Noun
A reflection prism used in optical instruments to alter the orientation of an image. It consists of a block of glass shaped as a right geometric prism with right-angled triangular end faces.
en eponyms