1) Having precedence 2) Senior 1) Senior 
• (a.) Of the nature of a precedent; having force as an example for imitation; as, precedential transactions.
Prec`e·den'tial adjective Of the nature of a precedent; having force as an example for imitation; as, precedential transactions. « All their actions in that time are not precedential to warrant posterity.» Fuller. 
[adj] - having precedence (especially because of longer service)
adjective having precedence (especially because of longer service); `precedential treatment for senior members of the firm`
of the nature of or constituting a precedent. · having precedence.