Synonyms of keystone

Noun

1. anchor, mainstay, keystone, backbone, linchpin, lynchpin, support

usage: 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"

2. keystone, key, headstone, building block

usage: the central building block at the top of an arch or vault

Definition and meaning of keystone (Dictionary)