underlie

American  

[uhn-der-lahy] / ˌʌn dərˈlaɪ /

verb (used with object)

underlay, underlain, underlying

1. to lie under or beneath; be situated under.

2. to be at the basis of; form the foundation of.

3. Grammar. to function as the root morpheme or original or basic form of (a derived form).

   The form “boy” underlies “boyish.”

4. Finance. to be primary to another right or security.

---

underlie British  

/ ˌʌndəˈlaɪ /

verb

1. to lie or be placed under or beneath

2. to be the foundation, cause, or basis of

   careful planning underlies all our decisions

3. finance to take priority over (another claim, liability, mortgage, etc)

   a first mortgage underlies a second

4. to be the root or stem from which (a word) is derived

   "happy" underlies "happiest"

---

Other Word Forms

• underlier noun

Etymology

Origin of underlie

before 900; Middle English underlyen (v.), Old English underlicgan. See under-, lie ²

Example Sentences

Anthropic is racing to contain the fallout after accidentally exposing the underlying instructions it uses to direct Claude Code, the popular artificial-intelligence agent app that has won the company an edge with developers and businesses.

From The Wall Street Journal

The exposed code related to the tool's internal architecture but does not contain confidential data from Claude, the underlying AI model by Anthropic.

From Barron's

"The report shows that the rise in prices at the pump is far greater than that of underlying crude oil prices," Greenpeace said in a statement.

From Barron's

Furthermore, the underlying instruments on which ETFs are based are less liquid than the ETFs themselves.

From MarketWatch

A 54-person crew researched and managed the portfolio of 4,100 or so underlying loans.

From The Wall Street Journal

Related Words

• control
• curb
• decide
• determine
• dominate
• guide
• handle
• inhibit
• manage
• regulate
• rule