early 15c., from O.Fr. assertion (14c.), from L.L. assertionem (nom. assertio), noun of action from L. asserere "claim rights over something, state, maintain, affirm," from ad- "to" + serere "join" (see series). By "joining oneself" to a particular view, one "claimed" or "maintained" it.
programming 1. An expression which, if false, indicates an error. Assertions are used for debugging by catching can't happen errors. 2. In logic programming, a new fact or rule added to the database by the program at run time. This is an extralogical or impure feature of logic programming languages. (1997-06-30)
[uh-sur-shuh
n] 
