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

Early prototypes shown at CES were assembled rapidly for demonstration, but Lumus says the underlying architecture avoids exotic materials. —Neetika Walter, Interesting Engineering, 9 Jan. 2026

For those gray area drinkers, that can mean reading books on drinking and sobriety, addressing underlying stresses and finding new ways to socialize. —Madeline Holcombe, CNN Money, 9 Jan. 2026

Critics quickly said that merely requiring payment does not address the underlying problems with the tool. —Victoria Craw, Washington Post, 9 Jan. 2026

Officials also noted that the child had no underlying health conditions. —Jessica Schladebeck, New York Daily News, 9 Jan. 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