Meaning & Definition of word "Theory"

Theory

ˈθiːəri

1. A supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.
- Example: The theory of evolution explains the diversity of life on Earth.
2. A set of principles on which the practice of an activity is based.
- Example: In music theory, we study the structure and fundamentals of music.
3. A conjecture or speculation.
- Example: She has a theory that the missing keys were taken by her younger brother.
4. An abstract reasoning; speculation.
- Example: The theory is that time travel could one day be possible.
5. A belief or opinion based on conjecture rather than knowledge.
- Example: His theory about the stock market is not backed by any empirical data.

From Greek 'theoria' meaning 'contemplation, speculation.'

grand theory:

A theory that attempts to explain a broad range of phenomena.

theory of everything:

A theoretical framework that aims to explain all fundamental forces and aspects of the universe.

out of theory:

To apply theoretical knowledge to practical situations.

hypothesis:

A testable prediction based on a theory.

principle:

A fundamental truth or proposition that serves as the foundation for a system of belief.

postulate:

A statement that is assumed to be true for the purposes of argument.

Meaning: Conspiracy theory

Example Sentence: He thinks the moon landing was a conspiracy theory.

Meaning: Theory crafting

Example Sentence: In gaming, theory crafting involves developing strategies based on game mechanics.