ˈthēətə̇n noun
( -s )
Usage: usually capitalized
Etymology: New Latin Theatinus, from Latin Teatinus inhabitant of Chieti, from Teate Chieti, Italy + -inus -ine; from the fact that one of the founders of the congregation was Giovanni P. Caraffa died 1559 Italian prelate, archbishop of Chieti and later Pope Paul IV
: a member of a Roman Catholic congregation of regular clerics established in 1524 in Italy to elevate clerical and lay morality and to combat Lutheranism