Source : Webster's Revised Unabridged Dictionary (1913)

Chelonian \Che*lo"ni*an\, a. (Zo["o]l.)
   Of or pertaining to animals of the tortoise kind. -- n. One
   of the Chelonia.

Source : WordNet®

chelonian
     adj : of or relating to or resembling or being a turtle or
           tortoise
     n : a reptile of the order Chelonia [syn: {chelonian reptile}]