1. A distinct part of a whole, especially:
   1. Linguistics. A syntactic unit of a sentence; a clause.
   2. Logic. A proposition of a syllogism.
   3. Mathematics. An element in a set.
2. A part or an organ of a human or animal body, as:
   1. A limb, such as an arm or a leg.
   2. The penis.
3. A part of a plant.
4. One that belongs to a group or an organization: a club member; a bank that is a member of the FDIC.
5. Mathematics. The expression on either side of an equality sign.
6. A structural unit, such as a beam or wall.

[Middle English membre, from Old French, from Latin membrum.]

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.