mainstay

A chief support.

A strong rope that serves to steady and support the mainmast of a sailing vessel.

plural All the stays which give support to the main lower mast, maintopmast, and maintopgallantmast.

The rope which secures the head of the mainmast of a vessel forward.

2. Chief support; main dependence: as, their mainstay is fishing.

The stay extending from the foot of the foremast to the maintop.

Main support; principal dependence.

A chief support.

A stabilising rope from the top of the mainmast to the bottom of the foremast.

a prominent supporter