The branch of mathematics dealing with the algebraic structure of fields. / (psychology) A theory which examines patterns of interaction between individuals and their environment.

(mathematics) A branch of mathematics which deals with spaces and maps between them in abstraction, taking similar theorems from various disparate more concrete branches of mathematics and unifying them.

(physics) A candidate unified theory of all physical forces and particles; a theory which suggests that subatomic particles are one-dimensional strings rather than zero-dimensional points. It also suggests that space-time can have up to nine dimensions, plus the dimension of time.

(physics) The theories of special relativity and general relativity, two theories in physics developed mainly by Albert Einstein at the beginning of the 20th century from which several important results such as the equivalence of matter and energy and the Einstein field equations are derived.

(dated) atomic theory

A theory developed by Terence McKenna that aims to describe "novelty" in the universe based on a combination of numerology and mathematics, and supposed fractal patterns in the I Ching.

(economics) A theory that abstinence in business will bring beneficial interest.

A mathematical technique for finding an approximate solution to a problem that cannot be solved exactly, by starting from the exact solution of a related problem; used in modelling physical interactions between particles, etc.

(psychology) The ability to form an opinion about what other people are thinking.

(physics) The theory that (most) baryons and mesons are composed of bound quarks and antiquarks.