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

The underlying practice, sometimes called contrast bath therapy or immersion therapy, alternates the body’s exposure to hot and cold water and has long been used by physical therapists, athletes and wellness enthusiasts, according to WHOOP. — Samantha Agate, Miami Herald, 20 Oct. 2026

Weber and other state officials also questioned the drop from 190,000 to 20,000, and the reliability of the federal government’s underlying data and methodology. — Kevin Rector, Los Angeles Times, 20 Oct. 2026

Analyzing them together helps cancel some random variations and isolate the underlying physics. — Kaif Shaikh, Interesting Engineering, 20 Oct. 2026

The second is a shift in the underlying science conversation. — Samantha Agate, Fort Worth Star-Telegram, 20 Oct. 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