a central cohesive source of support and stability
<noun.cognition> faith is his anchor the keystone of campaign reform was the ban on soft money he is the linchpin of this firm
the central building block at the top of an arch or vault
<noun.artifact>
Keystone \Key"stone`\, n. (Arch.) 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 Illust. of {Arch}.
The question of whether Hazelwood was drunk has been described by his lawyers as the keystone of the case, because it reflects on whether he acted recklessly as captain of the ship.
A December agreement by Texaco to settle with Pennzoil for $3 billion was the keystone of the reorganization plan ultimately approved by the court in April.
When the contracts were signed (GM and Ford in 1987, Chrysler in 1988), UAW leaders hailed the provision as a keystone in job security.
The Japanese in particular believe high-definition is the keystone to their competitiveness in the high-technology stakes.
A sense of lost control is also impressed on the mind of any observer of the federal bureaucracy, the cutting of which was a keystone of the platform on which Ronald Reagan was elected to the White House.
Once the keystone of the state's economy, the mile-wide mine at Butte known as "the richest hill on earth" was abandoned by Anaconda Co. in 1983, and although another concern has reopened it on a modest basis, the city remains deeply depressed.
"Our main desire is that next time to make sure that the rules of the road are absolutely clear." The keystone of U.S. securities law is the requirement that information be equally available to all market participants.
Philippine debt is politically entwined with the contentious issue of the six U.S. military bases, the keystone to American military power in the Western Pacific.