Dictionary.com
definitions

transilluminate

[trans-i-loo-muh-neyt, tranz-]
verb (used with object), trans·il·lu·mi·nat·ed, trans·il·lu·mi·nat·ing.
  1. to cause light to pass through.
  2. Medicine/Medical. to throw a strong light through (an organ or part) as a means of diagnosis.

Origin of transilluminate

First recorded in 1885–90; trans- + illuminate
Related formstrans·il·lu·mi·na·tion, nountrans·il·lu·mi·na·tor, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for transilluminate

transilluminate

verb
  1. (tr) med to pass a light through the wall of (a bodily cavity, membrane, etc) in order to detect fluid, lesions, etc
Derived Formstransillumination, nountransilluminator, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012