Webster's Revised Unabridged Dictionary · 1913

Nonone

Nonone , noun

[Nonane + -one, suffix denoting the third degree of unsaturation.]

1.
(Chemistry) Any one of several metameric unsaturated hydrocarbons (C9H14) of the valylene series. [archaic?]
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.