Source : Webster's Revised Unabridged Dictionary (1913)

Chortle \Chor"tle\, v. t. & i. [imp. & p. p. {Chortled}; p. pr.
   & vb. n. {Chor"tling}.]
   A word coined by Lewis Carroll (Charles L. Dodgson), and
   usually explained as a combination of chuckle and snort.
   [Humorous]

         O frabjous day ! Callooh ! Callay ! He chortled in his
         joy.                                     --Lewis
                                                  Carroll.

Source : WordNet®

chortle
     n : a soft partly suppressed laugh [syn: {chuckle}]
     v : laugh quietly or with restraint [syn: {chuckle}, {laugh
         softly}]