KEYSTONE


Meaning of KEYSTONE in English

I. ˈ ̷ ̷ˌ ̷ ̷ noun

Etymology: key (I) + stone

1. : the wedge-shaped piece at the crown of an arch ; especially : such a piece inserted last and locking the other pieces in place

2. : something analogous to the keystone of an arch in position or function : a part or force on which associated things depend for support

the keystone of his faith

keystone of a system of defense

as

a. : crushed stone of small size used in bituminous bound roads to fill the voids of the large aggregate — compare cover stone

b. : a bondstone in masonry

c. or keystone sack : second base in baseball

II. transitive verb

: to support by means of a keystone

III. noun

: a species of plant or animal that produces a major impact (as by predation) on its ecosystem and is considered essential to maintaining optimum ecosystem function or structure

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.