| Noun | 1. | mainstay - a prominent supporter; "he is a pillar of the community" | |
| 2. | mainstay - a central cohesive source of support and stability; "faith is his anchor"; "the keystone of campaign reform was the ban on soft money"; "he is the linchpin of this firm"support - something providing immaterial support or assistance to a person or cause or interest; "the policy found little public support"; "his faith was all the support he needed"; "the team enjoyed the support of their fans" | |
| 3. | mainstay - the forestay that braces the mainmastforestay - an adjustable stay from the foremast to the deck or bowsprit; controls the bending of the mast | |