English version

keystone in Construction topic

From Longman Dictionary of Contemporary Englishkeystonekey‧stone /ˈkiːstəʊn $ -stoʊn/ noun 🔊 🔊 1 TBC[countable] the large central stone in an arch that keeps the other stones in position2 IMPORTANT[singular] formal the most important part of an idea, belief, or process that influences how it developskeystone of 🔊 The keystone of any personal injury case is medical evidence.
Examples from the Corpus
keystone ofA high level of production has become a keystone of economic security.