Plymˈouthist, Plymˈouthite or Plymouth Brother noun

One of the Plymouth Brethren, a religious sect, founded in Dublin c.1825, out of a reaction against High Church principles and against a dead formalism associated with unevangelical doctrine (its first congregation was established at Plymouth in 1831)

Plymouth Rock noun

1. An American breed of poultry
2. A nickname for a Plymouth Brother