theorys

Theorys is not a standard English term. It is most often seen as a misspelling or typographical error for "theory" (singular) or "theories" (plural). In formal writing, the correct forms should be used.

In science and philosophy, a theory is a well-substantiated explanation of a broad range of phenomena. Theories unify diverse observations and make testable predictions. They are supported by evidence and may be revised or replaced in light of new data. A theory differs from a hypothesis, which is a testable conjecture, and from a law, which describes a consistent relationship under defined conditions.

Origin and pluralization: The word theory derives from Greek theoria meaning "contemplation" or "view," transmitted to English via Latin. In English, the plural is formed by adding -ies to the base ending with a consonant: theory → theories. The form theorys is normally incorrect in standard English, though it may appear in branding or personal names.

Usage notes: When encountering "theorys" in text, replace it with "theory" or "theories" as appropriate. Spell-checkers and style guides generally flag it as an error.

See also: Scientific theory; Hypothesis; Law (in science); Model; Paradigm.