apertometer

American

[ap-er-tom-i-ter] / ˌæp ərˈtɒm ɪ tər /

noun

Optics.

an instrument for measuring the angular and numerical aperture of the objective lens of a microscope.

First recorded in 1875–80; apert(ure) + -o- + -meter

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023