Source : Webster's Revised Unabridged Dictionary (1913)

Nonage \Non"age\, n. [LL. nonagium, from L. nonus ninth, novem
   nine.] (Eccl.)
   The ninth part of movable goods, formerly payable to the
   clergy on the death of persons in their parishes. --Mozley &
   W.

Nonage \Non"age\, n. [Pref. non- + age.]
   Time of life before a person becomes of age; legal
   immaturity; minority.

         The human mind . . . was still in its nonage.
                                                  --Coleridge.

Source : WordNet®

nonage
     n : any age prior to the legal age [syn: {minority}] [ant: {majority}]