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

The tackle is also one of the mainstays in the trenches for an offense that is effective running and passing the ball. — Shaun Chornobroff, Austin American Statesman, 5 Nov. 2026

It's been an 18-year journey to the top, as Asador Etxebarri has been a mainstay on The World's 50 Best Restaurants list since 2008, starting at number 44. — Nathan Tavares, Condé Nast Traveler, 5 Nov. 2026

But unless and until Starship demonstrates Falcon 9–like reliability, SpaceX’s shift away from its current mainstay seems destined to produce major ripple effects across the space industry, affecting numerous customers. — Ramin Skibba, Scientific American, 4 Nov. 2026

In terms of product categories, sales of the brand’s mainstay, the more formal Boss collection, eased 2 percent to 813 million euros. — Cathrin Schaer, Footwear News, 3 Nov. 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