Added 4 October 2026
undefined
adjective
adjective Definition from Wiktionary (CC BY-SA). More about undefined at Wordnik → Where our words come from →
- Lacking a definition or value.
-
That does not have a logically sound meaning within a specific formal system and is thus not assigned an interpretation.
The result of division by zero is undefined.
-
That behaves unreliably due to dependence on an uninitialized value or inconsistently ported code.
In C, relying on a variable's value right after a malloc call is undefined behvaior.
noun
- An undefined value.