Source : Webster's Revised Unabridged Dictionary (1913)

Viable \Vi"a*ble\, a. [F., from vie life, L. vita. See {Vital}.]
   (Law)
   Capable of living; born alive and with such form and
   development of organs as to be capable of living; -- said of
   a newborn, or a prematurely born, infant.

   Note: Unless he [an infant] is born viable, he acquires no
         rights, and can not transmit them to his heirs, and is
         considered as if he had never been born. --Bouvier.

Source : WordNet®

viable
     adj 1: capable of being done with means at hand and circumstances
            as they are [syn: {feasible}, {executable}, {practicable},
             {workable}]
     2: capable of life or normal growth and development; "viable
        seeds"; "a viable fetus"