seniority

/ˌsiːniˈɒrəti/ noun [U]

Definition

› the length of time you have worked for an organization, and the advantages that you get from this: Several people who had 30 years' seniority took the $140,000 lump sum on retiring. Pay ranges from $23,000 to $110,000 a year, depending on duties and seniority.

› the situation of having a higher rank than someone else in an organization: position of seniority.

(Definition of seniority noun from the Cambridge Business English Dictionary © Cambridge University Press)