noun

1. The act of asserting; positive declaration or averment.

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

   "You're a man of strong assertions!"

3. A statement or declaration which lacks support or evidence.

   "That's just a bare assertion."

4. Maintenance; vindication

   "the assertion of one's rights or prerogatives"

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