Definitions
the central building block at the top of an arch or vault
Word origin
From key + stone.
Used in a sentence
“The tunnel, which is 1,000 yd. long, had been closed to passenger traffic since November 17, 1949, after some of the keystones had worked loose.”
“Tension between empirical and theoretical knowledge is keystone to sociological and to organizational theories, as early as in Marx's and Weber's frameworks.”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer2 curated clues
01“Central support”8 letters
02“Arch center”8 letters
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