mother church
noun
Definitions
The Church regarded as nourishing and protecting its members.
Example: Catholics regard Mary as Mother of the Church but an all-male hierarchy as the Mother Church.
A church with oversight over another or others, now especially a cathedral or metropolitan church.
Example: Mothering Sunday arose from the custom of visiting mother churches at Mid-Lent, rather than the usual parish church.
The original church of a denomination, regarded as having birthed the others.
Example: The mother church of Christian Scientists is in Boston, Massachusetts.
The original denomination or community of believers from which other denominations and communities of believers sprang.
Example: The Church of England is the mother church of Anglicans around the world.