noun
Usage: usually capitalized P
: any of several large brilliantly colored chiefly tropical siphonophores (genus Physalia ) that float on the surface of the sea by means of a large bladderlike pneumatophore with a crest like a sail on its upper side and with a cluster of zooids at one side of the lower surface equipped with numerous powerful nematocysts capable of causing serious injury to man and including very long tentacular dactylozooids and much shorter gastrozooids and gonozooids
[s]portugue.jpg[/s] [
Portuguese man-of-war
]