GNU Collaborative International Dictionary of English

Found one definition

1.       
   Nonone (?), n. [Nonane + -one, suffix denoting the third degree of unsaturation.] (Chem.)
   1. Any one of several metameric unsaturated hydrocarbons (C9H14) of the valylene series.  [archaic?]
   
   [1913 Webster]
   
   
   2. Any of several isomeric ketones (C9H18O) conceptually derived from nonane by substituting an oxygen for two hydrogen atoms on one of the non-terminal carbon atoms.
   
   [PJC]