n 1  :  a weakly basic organic compound C₄H₂N₂ of penetrating odor that is composed of a single six-membered ring having four carbon atoms with nitrogen atoms in positions one and three  2  :  a derivative of pyrimidine having its characteristic ring structure : esp  :  a base (as cytosine, thymine, or uracil) that is a constituent of DNA or RNA .
 
   
 
Similar sounding terms:  para·me·di·an  pri·mi·done 
 
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