'Seniority' definitions:

Definition of 'seniority'

From: WordNet
noun
Higher rank than that of others especially by reason of longer service [syn: seniority, senior status, higher status, higher rank]
noun
The property of being long-lived [syn: longevity, seniority]

Definition of 'Seniority'

From: GCIDE
  • Seniority \Sen*ior"i*ty\, n. The quality or state of being senior. [1913 Webster]