Undefined
Undefined may refer to:

Mathematics
Undefined (mathematics), with several related meanings
Indeterminate form, in calculus

Computing
Undefined behavior, computer code whose behavior is not specified under certain conditions
Undefined value, a condition where an expression does not have a correct value
Undefined variable
Undefined, a function or variable lacking a declaration
Undefined, a variable lacking initialization
Undefined, an unavailable linker symbol (function, or global variable)

Other uses
Undefined, something that lacks any definition
Undefined citizenship, a post-Soviet form of statelessness in Estonia

See also
Null (disambiguation)
Void (disambiguation)
Invalid (disambiguation)
Definition (disambiguation)
Definable (disambiguation)
All pages with titles beginning with Undefined