senior senior /ˈsiːnjɝ/

adjective

1. () Older; higher in rank; longer in length of tenure or service  ( senior )
   older; higher in rank; longer in length of tenure or service
    Senior officer
   senior officer
   
2. () Used of the fourth and final year in United States high school or college  ( fourth-year , senior )
   used of the fourth and final year in United States high school or college
    The senior prom
   the senior prom
   
3. Advanced in years; (aged' is pronounced as two syllables)  ( senior , aged , elderly , older )
   advanced in years; (aged' is pronounced as two syllables)
    Aged members of the society
   aged members of the society
    Elderly residents could remember the construction of the first skyscraper
   elderly residents could remember the construction of the first skyscraper
    Senior citizen
   senior citizen
   

noun

1. () An undergraduate student during the year preceding graduation  ( senior )
   an undergraduate student during the year preceding graduation
     The wise senior offered valuable advice based on years of experience.
   The wise senior offered valuable advice based on years of experience.
   
2. A person who is older than you are  ( senior , elder )
   a person who is older than you are
     The elder members of the community shared their wisdom and experiences.
   The elder members of the community shared their wisdom and experiences.