trĭērarchus, i, m., = τριήραρχος,
the captain of a trireme , a trierarch , Cic. Verr. 2, 1, 20, § 52; Tac. H. 2, 16; Suet. Ner. 34; Inscr. Orell. 2652; 3595; 3603; 3615 sq.
triērarchus ī, m , τριήραρχος, a captain of a trireme, trierarch. ...
An Elementary Latin Dictionary