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

• anchor
• buttress
• dependence
• dependance
• pillar
• reliance
• 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

This package also provides approximately 2,000 High Mobility Multipurpose Wheeled Vehicles (HMMWV), commonly referred to as Humvees, durable light military trucks that have been a mainstay of U.S. ground forces since the 1980s. —Vikram Mittal, Forbes, 29 Oct. 2024

But the principle is a mainstay of math class and enables the calculation of the length of any side of a right-angled triangle — as long as the lengths of the other two sides are known. —Katie Hunt, CNN, 29 Oct. 2024

Garr was also a late night TV mainstay, having made frequent appearances on The Tonight Show Starring Johnny Carson and Late Night with David Letterman. —Michael Ausiello, TVLine, 29 Oct. 2024

While creamy white walls will always be a mainstay, people are getting bolder and more confident with color. —Cameron Beall, Southern Living, 26 Oct. 2024

Word History

First Known Use

15th century, in the meaning defined at sense 2

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