the·o·ry (thēə-rē, thîrē)
n. pl. the·o·ries
1. A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.
2. The branch of a science or art consisting of its explanatory statements, accepted principles, and methods of analysis, as opposed to practice: a fine musician who had never studied theory.
3. A set of theorems that constitute a systematic view of a branch of mathematics.
4. Abstract reasoning; speculation: a decision based on experience rather than theory.
5. A belief or principle that guides action or assists comprehension or judgment: staked out the house on the theory that criminals usually return to the scene of the crime.
6. An assumption based on limited information or knowledge; a conjecture.
[Late Latin theōria, from Greek theōriā, from theōros, spectator : probably theā, a viewing + -oros, seeing (from horān, to see).]
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
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