Source : Webster's Revised Unabridged Dictionary (1913)

Longevity \Lon*gev"i*ty\, n. [L. longaevitas. See {Longevous}.]
   Long duration of life; length of life.

         The instances of longevity are chiefly amongst the
         abstemious.                              --Arbuthnot.

Source : WordNet®

longevity
     n 1: duration of service; "her longevity as a star"; "had unusual
          longevity in the company" [syn: {length of service}]
     2: the property of being long-lived [syn: {seniority}]