Portuguese man-of-war

WordReference Random House Unabridged Dictionary of American English © 2026

Por′tuguese man-of-war′, 

1. Invertebrates 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.

• 1700–10

Collins Concise English Dictionary © HarperCollins Publishers::

Portuguese man-of-war noun

1. any of several large complex colonial hydrozoans of the genus Physalia, esp P. physalis, having an aerial float and long stinging tentacles: order Siphonophora
   Sometimes shortened to: man-of-war