Wordnet 3.0
NOUN (1)
1. 
 marine fishes having a tapering body with an armored head and venomous spines; 
[syn: scorpionfish, scorpion fish, sea scorpion]
The Collaborative International Dictionary of English v.0.48:
Sea scorpion \Sea" scor"pi*on\ (Zool.)
   (a) A European sculpin (Cottus scorpius) having the head
       armed with short spines.
   (b) The scorpene.
       [1913 Webster]
WordNet (r) 3.0 (2006):
sea scorpion
    n 1: marine fishes having a tapering body with an armored head
         and venomous spines [syn: scorpionfish, scorpion fish,
         sea scorpion]