nav·i·ga·ble / ˈnavigəbəl/ • adj. 1. (of a waterway or sea) able to be sailed on by ships or boats. ∎  (of a track or road) suitable for transportation; passable: those minor roads would be navigable in emergencies. ∎  (esp. of a Web site) easy to get around in; maneuverable: a navigable Web browser.2. (of a vessel) properly equipped, maintained, and operated.DERIVATIVES: nav·i·ga·bil·i·ty / ˌnavəgəˈbilitē/ n.

navigable XVI. — F. navigable or L. nāvigābilis. f. nāvigāre (whence navigate XVI), f. nāvis ship (see NAVAL) + -ig-, comb. stem of agere drive (see ACT).
So navigation XVI. — (O)F. or L. navigator XVI. — L.