Definition of T–number
: a number that is similar to the f-number but takes into account the amount of light actually transmitted by a lens after loss by absorption and reflection and that equals the f-number divided by the square root of the transmittance
Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.
Join MWU now and get access to America’s largest dictionary, with:
- 300,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Origin and Etymology of t–number
total light transmission + number
Seen and Heard
What made you want to look up T–number? Please tell us where you read or heard it (including the quote, if possible).