Definition of church union in English:

church union

noun

  • (Originally) unity or solidarity within the church; (later) the formal union of churches; an instance of this; (Canadian) the merger, brought about in 1925, of Canadian Methodist and Congregationalist Churches together with the majority of Canadian Presbyterians to form the United Church of Canada.

Origin

Early 17th century; earliest use found in John Robinson (d. 1625), Church of England clergyman and separatist theologian.