Premise (noun)

1. A statement or assumption on which a conclusion is based.
2. A statement or idea that is used as a starting point for a piece of writing, argument, or theory.
3. A set of basic ideas or propositions that provide the foundation for a belief, theory, or a work of fiction.
4. A building or group of buildings with a particular purpose, such as a school or hospital.
5. The underlying reason or principle behind a situation or decision.

Origin:

Late 16th century: from latin praemissum, neuter past participle of praemittere 'send before', from prae 'before' + mittere 'send'. the verb (late 16th century) comes from the noun.

Examples:

1. The premise of the argument was that everyone should have equal rights.
2. The premise of the book was that a better world was possible.
3. The premises of the school were surrounded by a large playground.
4. The company's premise was that technology could change the world.
5. The premise of the film was that a group of aliens had invaded Earth.