1. Being only one; individual.
2. Being the only one of a kind; unique.
3. Being beyond what is ordinary or usual; remarkable.
4. Deviating from the usual or expected; odd. See synonyms at strange.
5. Grammar.
   1. Of, relating to, or being a noun, pronoun, or adjective denoting a single person or thing or several entities considered as a single unit.
   2. Of, relating to, or being a verb expressing the action or state of a single subject.
6. Logic. Of or relating to the specific as distinguished from the general; individual.

1. The singular number or a form designating it.
2. A word having a singular number.

[Middle English singuler, from Old French, from Latin singulāris, from singulus, single. See single.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.