Source : Webster's Revised Unabridged Dictionary (1913)

Countless \Count"less\ (-l?s), a.
   Incapable of being counted; not ascertainable; innumerable.

Source : WordNet®

countless
     adj : too numerous to be counted; "incalculable riches";
           "countless hours"; "an infinite number of reasons";
           "innumerable difficulties"; "the multitudinous seas";
           "myriad stars"; "untold thousands" [syn: {infinite}, {innumerable},
            {innumerous}, {myriad(a)}, {multitudinous}, {numberless},
            {uncounted}, {unnumberable}, {unnumbered}, {unnumerable}]