Portuguese man-of-war UK /ˈpɔː.tʃʊˌɡiːz ˌmæn.ə(v)ˈwɔː/US /ˈpoɹ.tʃəˌɡiz ˌmæn.ə(v)ˈwoɹ/ noun1 •Physalia physalis, a marine cnidarian consisting of a floating colony of hydrozoans attached to a float, superficially resembling a jellyfish.However, two beaches in Tarragona in southern Catalonia were closed in July after Portuguese man o’war (Physalia physalis) were spotted in the water. — 2024 formsPortuguese men-of-war