English dictionary

keystone

/'k/i/,st/oU/n/

Definitions, examples, synonyms and antonyms from WordNet 3.0.

noun

a central cohesive source of support and stability

noun.cognition

Examples
The keystone of campaign reform was the ban on soft money.

Synonyms anchor backbone linchpin lynchpin mainstay

Source: WordNet 3.0
the central building block at the top of an arch or vault

noun.artifact

Synonyms headstone key

Source: WordNet 3.0
The central or topmost stone of an arch. This in some styles is made different in size from the other voussoirs, or projects, or is decorated with carving. See <i>Illust.</i> of <u>Arch</u>.

noun

Source: webster1913