What is the meaning of Assertion?

The act of asserting; positive declaration or averment.

Something which is asserted; a declaration; a statement asserted.

A statement or declaration which lacks support or evidence.

Maintenance; vindication

A statement in a program asserting a condition expected to be true at a particular point, used in debugging.

the set of information that the statement preparer is providing in a financial statement audit.

assertion

Source: wiktionary.org