) KEY NOUN: pl. the·o·ries
- 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.
- 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.
- A set of theorems that constitute a systematic view of a branch of mathematics.
- Abstract reasoning; speculation: a decision based on experience rather than theory.
- 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.
- An assumption based on limited information or knowledge; a conjecture.
Late Latin theria
, from Greek theri
, from theros
: probably the
, a viewing
, to see