Theory

Research

A well-supported explanatory system, distinct from a hypothesis (a specific testable prediction) and from the colloquial "just a theory."

Sources

1. Merriam-Webster — theory merriam-webster.com accessed 23 September 2026

Merriam-Webster’s scientific sense is the one that settles the usual argument: “a scientifically acceptable or plausible general principle or body of principles based on data and offered to explain phenomena”, alongside “a hypothetical structure explaining or relating to an observed set of facts”. The dictionary adds the distinction directly: while both words are used loosely to mean a hunch, “a theory is understood to be much more likely to be true than a hypothesis is, and is in fact relied upon for further scientific investigations”. From Greek theōrein, to view or consider; first recorded 1588. “Only a theory” inverts the actual hierarchy.

Merriam-Webster is cited as the dictionary of record: where an entry defines a word rather than a position, a dictionary is the primary source for it. The research usage above is this lexicon’s own.

Related terms

• Abbreviation
• Abstract
• Abstraction
• Academic Database
• Analysis
• Annotation

From the AJG lexicon archive (July 2026).