# underlie

/ˌəndɝˈɫaɪ/ (US) · /ˌʌndəlˈaɪ/ (UK) · CEFR C1 · Verb

Source: https://englishreference.com/word/underlie
Updated: 2026-10-13

## Definition

to be the hidden support or reason behind something. You use it when one idea or fact explains why something else happens.

For teachers: to form the basis or foundation of a system, argument, or phenomenon; to lie beneath either physically or conceptually.

## Examples

- Strong values underlie their family decisions every day.
- Economic fears underlie much of the anger voters expressed during the town hall meeting.
- The quiet belief that hard work is always rewarded underlies much of the novel's moral argument, even when the plot shows the opposite.

## Usage notes

- The verb is transitive and takes a direct object. Past tense 'underlay', past participle 'underlain', present participle 'underlying'.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.