mainstay

noun

main·​stay ˈmān-ˌstā 

plural mainstays

1

a

: a crucial or key part of something

Fish is the mainstay of their diet.

Tourism is a mainstay of the city's economy.

The mainstay of treatment for chronic hives of unknown origin is antihistamine medications.

—Mayo Clinic Health Letter

b

: someone or something that is a principal or reliable support or resource

Tourism is one of the city's economic mainstays.

Her immense pride in him and unquestioning support were among the few mainstays in his life.

—Robert V. Remini

2

: a ship's stay (see stay entry 1 sense 1) extending from the maintop forward usually to the foot of the foremast

Synonyms of mainstay

• anchor
• backbone
• pillar
• standby

Examples of mainstay in a Sentence

Fish is a mainstay of their diet.

My mother has always been the mainstay of our family.

Recent Examples on the Web

During recent earnings calls with analysts, executives from American mainstays such as Walmart, McDonald’s and Dollar General cited overall shopper resilience as well as noticeable cutbacks by lower-income customers. —Anne D’innocenzio, Los Angeles Times, 8 June 2026

That review has been a mainstay of America's health system, with the FDA acting as a gatekeeper to protect the public from unsafe or ineffective drugs. —Daniel Gilbert, CBS News, 8 June 2026

There is no typical Saturday at the vascular surgery clinic at Mass General, but the mainstays are doctors, nurse practitioners, nurses, and ultrasound technicians assisted by medical students and medical residents. —Elizabeth Cooney, STAT, 8 June 2026

But consider starting with a classic experience at James Beard awarding-winning La Taqueria, a mainstay for more than half a century. —Becky Duffett, Bon Appetit Magazine, 8 June 2026

Word History

First Known Use

15th century, in the meaning defined at sense 2

Rhymes for mainstay

• airway
• allay
• archway
• array
• ashtray
• assez
• astray
• aue
• away
• ballet
• belay
• beltway

Kids Definition

mainstay

noun

main·​stay -ˌstā 

1

: a large strong rope running from the maintop of a ship usually to the foot of the foremast

2

: a chief support

the mainstay of the family