The meaning of UNDEFINED is not defined. How to use undefined in a sentence.

UNDEFINED meaning: 1. not clearly described, stated, or known: 2. not having been given a definition (= a statement…. Learn more.

Jan 10, 2026 · You can use undefined and the strict equality and inequality operators to determine whether a variable has a value. In the following code, the variable x is not initialized, and the if …

Look up undefined in Wiktionary, the free dictionary.

Definition of 'undefined' undefined in British English (ˌʌndɪˈfaɪnd ) adjective not defined or made clear

Definition of undefined adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

1. not defined or explained. 2. indefinite in form or extent: an undefined feeling of sadness.

UNDEFINED definition: without fixed limits; indefinite in form, extent, or application. See examples of undefined used in a sentence.

Dec 14, 2025 · (mathematics, computing) That does not have a meaning and is thus not assigned an interpretation. The result of division by zero is undefined.

Feb 22, 2011 · As typeof returns undefined, undefined is a type where as null is an initializer indicates the variable points to no object (virtually everything in Javascript is an object).