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

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 …

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

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

without fixed limits; indefinite in form, extent, or application: undefined authority; undefined feelings of sadness. not given meaning or significance, as by a definition;

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.