keystone

US /ˈkiː.stoʊn/
UK /ˈkiː.stoʊn/
"keystone" picture
1.

batu kunci

a central stone at the summit of an arch, locking the whole together

:
The architect carefully placed the keystone to complete the arch.
Arkitek dengan teliti meletakkan batu kunci untuk melengkapkan gerbang.
Without the keystone, the entire structure would collapse.
Tanpa batu kunci, seluruh struktur akan runtuh.
2.

teras utama, asas

the central principle or part of a policy, system, etc., on which all others depend

:
Education is the keystone of a prosperous society.
Pendidikan adalah teras utama masyarakat yang makmur.
The new policy is the keystone of their economic reform.
Dasar baharu itu adalah teras utama pembaharuan ekonomi mereka.