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 friction could harm some people with underlying skin conditions, too. —Nicole Fallert, USA Today, 11 Dec. 2025

Still, China’s soaring trade surplus cannot obscure its underlying economic troubles. —John Liu, CNN Money, 11 Dec. 2025

The underlying proposal, spearheaded by Fitzpatrick, would extend the tax credits through 2027 and impose a cap on income for those who are eligible for the subsidies. —Caitlin Yilek, CBS News, 10 Dec. 2025

While the terminator model has caught on, plenty of other ways of thinking about the sun exist—some of them with more physics reasoning underlying them. —Sarah Scoles, Scientific American, 10 Dec. 2025

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