underlie

verb

un·​der·​lie ˌən-dər-ˈlī 

underlay ˌən-dər-ˈlā  ; underlain ˌən-dər-ˈlān  ; underlying ˌən-dər-ˈlī-iŋ 

transitive verb

1

: to lie or be situated under

2

: to be at the basis of : form the foundation of : support

ideas underlying the revolution

3

: to exist as a claim or security superior and prior to (another)

4

archaic : to be subject or amenable to

Examples of underlie in a Sentence

A tile floor underlies the rug.

The river is underlain by limestone.

We discussed the principles that underlay their methods.

A theme of revenge underlies much of her writing.

Recent Examples on the Web

While the concept is not a mandate in the EU AI Act, the underlying documentation the act requires closely aligns with what an AI-BOM contains. — Akash Pugalia, Forbes.com, 17 July 2026

But at a press briefing on Thursday, Carney said the underlying agreement with Michigan on the Gordie Howe bridge remained unchanged from 2012, when Canada agreed to front the cost of the bridge. — Maria Cheng, USA Today, 17 July 2026

For example, a heart attack, which can be triggered by extreme heat exposure, especially in people who are older or have underlying health issues, may be listed on a death certificate simply as a heart attack. — ABC News, 17 July 2026

Earlier this month, Warner Bros won a five-studio bidding war with a multi-million-dollar deal for the underlying rights to Siren Head, a viral horror meme that is behind billions of views across TikTok, YouTube and Roblox. — Mia Galuppo, HollywoodReporter, 17 July 2026

Word History

First Known Use

before the 12th century, in the meaning defined at sense 4

Rhymes for underlie

• apply
• awry
• belie
• bely
• bigeye
• bonsai
• buckeye
• comply
• coxae
• decry
• defy
• deny

Kids Definition

underlie

verb

un·​der·​lie ˌən-dər-ˈlī 

underlay -ˈlā  ; underlain -ˈlān  ; underlying -ˈlī-iŋ 

1

: to lie or be located under

2

: to form the foundation of : support

ideas underlying the revolt