cornerstone
US /ˈkɔːr.nɚ.stoʊn/
UK /ˈkɔːr.nɚ.stoʊn/

1.
piedra angular, base
an important quality or feature on which a particular thing depends or is based
:
•
Trust is the cornerstone of any strong relationship.
La confianza es la piedra angular de cualquier relación sólida.
•
Education is the cornerstone of a prosperous society.
La educación es la piedra angular de una sociedad próspera.
2.
piedra angular
a stone that forms the base of a corner of a building, especially one laid at a formal ceremony
:
•
The mayor laid the cornerstone for the new library.
El alcalde colocó la piedra angular de la nueva biblioteca.
•
The date of construction was carved into the cornerstone.
La fecha de construcción estaba grabada en la piedra angular.