vi·a·ble / ˈvīəbəl/ • adj. capable of working successfully; feasible: the proposed investment was economically viable. ∎  Bot. (of a seed or spore) able to germinate. ∎  Biol. (of a plant, animal, or cell) capable of surviving or living successfully, esp. under particular environmental conditions. ∎  Med. (of a fetus or unborn child) able to live after birth.DERIVATIVES: vi·a·bil·i·ty / ˌvīəˈbilətē/ n.vi·a·bly / -blē/ adv.

viable capable of living or existing. XIX. — F., f. vie life (:- L. vīta); see -ABLE.
So viability XIX.

viable (vy-ăbŭl) adj. capable of living a separate existence. The legal age of viability of a fetus is 24 weeks, but some fetuses now survive birth at an even earlier age.