Definition of seniors:
(adj) :
(US) Of or pertaining to a student's final academic year at a high school (twelfth grade) or university.
(adj) :
Higher in rank, dignity, or office; superior.
(adj) :
Older.
(n) :
(now chiefly US) An old person.
(n) :
Someone older than someone else (with possessive).
(n) :
Someone seen as deserving respect or reverence because of their age.