'Navigability' definitions:

Definition of 'navigability'

From: WordNet
noun
The quality of being suitable for the passage of a ship or aircraft

Definition of 'Navigability'

From: GCIDE
  • Navigability \Nav`i*ga*bil"i*ty\, n. [Cf. F. navigabilit['e].] The quality or condition of being navigable; navigableness. [1913 Webster]