| any of several large, oceanic hydrozoans of the genus Physalia, having a large, bladderlike structure with a saillike crest by which they are buoyed up and from which dangle tentacles with stinging cells. |
| Portuguese man-of-war n. A complex colonial siphonophore of the genus Physalia, of warm seas, having a bluish bladderlike float with a broad saillike crest from which hang numerous long stinging tentacles. |
