cornerstone

noun
/ˈkɔː.nə.stəʊn/

A stone forming the base at the corner of a building.

Other meanings

Such a stone used ceremonially, often inscribed with the architect's and owner's names, dates and other details.
“The cornerstone on the Flatiron Building is set on the Fifth Avenue facade.”
That which is prominent, fundamental, noteworthy, or central.
“Exceptional service is the cornerstone of the hospitality industry.”

Synonyms

basis
base
foundation

Example sentences

“Trust is the cornerstone of every relationship.”
Tatoeba · Igider · CC0
“The means used to prepare the future become its cornerstone.”
Tatoeba · shekitten · CC0

Word history

From Middle English "corner ston".

Where this comes from

This definition is adapted from “cornerstone” on Wiktionary, by its contributors; example sentences are from Tatoeba, credited to their authors above; related-word lists use Open English WordNet (CC BY 4.0, based on Princeton WordNet), published under CC BY-SA 4.0. This page is published under the same licence.