1. The state or quality of being one; singleness.
2. The state or quality of being in accord; harmony.
3. 1. The combination or arrangement of parts into a whole; unification.
   2. A combination or union thus formed.
4. Singleness or constancy of purpose or action; continuity: "In an army you need unity of purpose" (Emmeline Pankhurst).
5. 1. An ordering of all elements in a work of art or literature so that each contributes to a unified aesthetic effect.
   2. The effect thus produced.
6. One of the three principles of dramatic structure derived by French neoclassicists from Aristotle's Poetics, stating that a drama should have but one plot, which should take place in a single day and be confined to a single locale.
7. Mathematics.
   1. The number 1.
   2. See identity element.

[Middle English unite, from Old French, from Latin ūnitās, from ūnus, one.]

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.