1. The act of including or the state of being included.
2. Something included.
3. A solid, liquid, or gaseous foreign body enclosed in a mineral or rock.
4. A nonliving mass, such as a droplet of fat, in the cytoplasm of a cell.
5. Computers A logical operation that assumes the second statement of a pair is true if the first one is true.
[Latin inclūsiō, inclūsiōn-, from inclūsus, past participle of inclūdere, to enclose; see INCLUDE.]
in·clusion·ar′y (-zhə-nĕr′ē) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.