mainstay

[ meyn-stey ]
/ ˈmeɪnˌsteɪ /

noun

Nautical. the stay that secures the mainmast forward.
a person or thing that acts as a chief support or part: Coffee is the mainstay of the country's economy.

Origin of mainstay

First recorded in 1475–85; main1 + stay2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for mainstay

British Dictionary definitions for mainstay

mainstay
/ (ˈmeɪnˌsteɪ) /

noun

nautical the forestay that braces the mainmast
a chief support
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012