n 1  :  any of three isomeric carbonyl compounds C₃H₄N₂O derived from pyrazoline  2  :  any of various derivatives of the pyrazolones some of which (as antipyrine) have been used as analgesics and antipyretics .
 
 
 
Similar sounding terms:  por·ce·lain  py·raz·o·line 
 
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