The Collaborative International Dictionary of English v.0.48:

Diethylamine \Di*eth`yl*am"ine\, n. [Pref. di- + ethylamine.]
   (Chem.)
   A colorless, volatile, alkaline liquid, NH(C2H5)2, having a
   strong fishy odor resembling that of herring or sardines. Cf.
   Methylamine.
   [1913 Webster]