1. A distinct part of a whole, especially:
a. Linguistics A syntactic unit of a sentence; a clause.
b. Logic A proposition of a syllogism.
c. Mathematics An element in a set.
2. A part or an organ of a human or animal body, as:
a. A limb, such as an arm or a leg.
b. The penis.
3. A part of a plant.
4. One that belongs to a group or 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, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.