Source : Webster's Revised Unabridged Dictionary (1913)

AEonian \[AE]*o"ni*an\, a. [Gr. ?.]
   Eternal; everlasting. ``[AE]onian hills.'' --Tennyson.

Source : WordNet®

aeonian
     adj 1: of or relating to a geological eon (longer than an era)
            [syn: {eonian}]
     2: lasting for an indefinitely long period of time [syn: {everlasting},
         {eternal}, {lasting}, {eonian}]