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

O'Hara died in January from a pulmonary embolism, with rectal cancer as the underlying cause, according to a death certificate obtained by Fox News Digital. —Tracy Wright, FOXNews.com, 2 Mar. 2026

This can be thought of as the background hum of the universe from a host of more distant collision events underlying that loud crashing orchestra of relatively close massive black hole mergers. —Robert Lea, Space.com, 2 Mar. 2026

There still has to be, after Bruen and after Rahimi, a historical principle to underlie that determination. —Melissa Quinn, CBS News, 1 Mar. 2026

While traditional facelifts merely tighten the skin in a superficial manner, deep-plane procedures can now reorganize the underlying structure of the face, repositioning muscles, fat pads, and ligaments in a labile system of roving features. —Patrick R. Crowley, Artforum, 1 Mar. 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