Definition of autocollimation
: the process of collimating an instrument (such as a telescope) having objective and cross hairs by directing it toward a plane mirror and adjusting the lens and cross hairs so that the latter coincide with their own reflected image
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.
Start your free trial today and get unlimited access to America's largest dictionary, with:
- More than 250,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Origin and Etymology of autocollimation
aut- + collimation
First Known Use: 1870
Seen and Heard
What made you want to look up autocollimation? Please tell us where you read or heard it (including the quote, if possible).