2. A statement containing an illogical conclusion.
3. In logic, a conclusion that does not follow from the premises.
A non sequitur is a literary device; in comedy, it is a comment which, due to its lack of meaning relative to the comment it follows, is absurd to the point of being humorous. Its use can be deliberate or unintentional. Literally, it is Latin for "it does not follow".
In other literature, a non sequitur can denote an abrupt, illogical, unexpected, or absurd turn of plot or dialogue not normally associated with or appropriate to that which preceded it.