noun
cornerstone
noun
1
A stone set at the base corner of a building, sometimes laid ceremonially with an inscription.
"The mayor laid the cornerstone of the new library in 1925."
2
The fundamental basis or most important part of something.
"Trust is the cornerstone of any strong marriage."
How to Use Cornerstone
Learner’s notesIn plain EnglishA foundation stone of a building, or figuratively the essential basis of something.
Common pairings
cornerstone of
lay the cornerstone
Word Forms
cornerstones plural
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The mayor laid the _____ of the new library in 1925.
Etymology
From Middle English "corner ston"; the figurative sense echoes a well-known biblical image found in Psalms and repeated in the New Testament.