undefined

Lacking a definition or value.

Adjective

  1. Lacking a definition or value.
    • We slid into our office, past two women discussing the "X factor," an apparently undefined quality their firm felt they lacked. - 1992, Lia Matera, Prior Convictions, page 121:
  2. That does not have a meaning and is thus not assigned an interpretation.
    • The result of division by zero is undefined.

Origin

Etymology tree Proto-Indo-European *né Proto-Indo-European *n̥- Proto-Germanic *un- Proto-West Germanic *un- Old English un- Middle English un- English un- English defined English undefined From un- + defined.

Synonyms

indefinite undefinable vague

Antonyms

defined

Derived

undefined behavior

Noun

  1. An undefined value.
    • [Option:] · [PDP11:] F [BSD:] · [XE 2.3:] [1] [XE 3.0:] · [SIII:] · [COFF:] · [meaning:] make undefineds global - 1987, J. E. Lapin, Portable C and UNIX System Programming (Prentice-Hall Software Series), Englewood...
    • Every operation is defined completely either by delivering a value of some type depending only on the types of its operands or by causing some defined exception; there are no ‘undefineds’ in Ten15. - 1988, Pearl...
    • The Array object has these commonly-used properties: • .length: the number of items including undefineds. - 2017, Neos. Thanh, “Arrays”, in JavaScript Programming, →ISBN, page 36:

Forms

undefineds