ˈ ̷ ̷ˌ ̷ ̷ noun
Etymology: Middle English mayne stay, from mayne, mayn main + stay
1. : a ship's stay extending from the maintop forward usually to the foot of the foremast — see ship illustration
2. : chief support : principal reliance
she has been a mainstay of several small luncheon clubs — Robert Rice
cotton is the mainstay of the surrounding country — American Guide Series: Louisiana