
1) Non-SI metric unit
Found on
https://www.crosswordclues.com/clue/troland

The troland (symbol Td), named after Leonard T. Troland, is a unit of conventional retinal illuminance. It is meant as a method for correcting photometric measurements of luminance values impinging on the human eye by scaling them by the effective pupil size. It is equal to retinal illuminance produced by a surface whose luminance is one nit when ...
Found on
http://en.wikipedia.org/wiki/Troland

unit used to express a quantity proportional to retinal illuminance produced by a light stimulus. When the eye is viewing a surface of uniform luminance, the number of trolands is equal to the product of area in square milimetres of the limiting pupil, natural or artificial, by the luminance of the surface in candelas per square metre NOTE 1 - In c...
Found on
http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=845-02-16

A unit of visual stimulation at the retina equal to the illumination per square millimeter of pupil received from a surface of 1 lux brightness. ... Origin: L.T. Troland, U.S. Physicist, 1889-1932 ... (05 Mar 2000) ...
Found on
http://www.encyclo.co.uk/local/20973

Type: Term Pronunciation: trō′lănd Definitions: 1. L.T., U.S. physicist, 1889-1932. See: troland
Found on
http://www.medilexicon.com/medicaldictionary.php?t=94147
No exact match found.