Definition of alnus
1 capitalized : a genus of alders (family Betulaceae) found in the north temperate zone and the Andes and having toothed leaves, a 4-parted calyx, and a woody conelike fruit
2 plural -s : any plant of the genus Alnus
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 alnus
New Latin, from Latin, alder — more at alder
First Known Use: 1733
Seen and Heard
What made you want to look up alnus? Please tell us where you read or heard it (including the quote, if possible).