Definition of AR15
: a . 223 caliber gas-operated semiautomatic rifle that is essentially a civilian version of the M16
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 ar15
from Armalite, the manufacturer
First Known Use: 1963See Words from the same year
Seen and Heard
What made you want to look up AR15? Please tell us where you read or heard it (including the quote, if possible).