(n.) One in the fourth or final year of his collegiate course at an American college; - originally called senior sophister; also, one in the last year of the course at a professional schools or at a seminary.

(3):

(a.) Belonging to the final year of the regular course in American colleges, or in professional schools.

(4):

(a.) More advanced than another in age; prior in age; elder; hence, more advanced in dignity, rank, or office; superior; as, senior member; senior counsel.

(5):

(n.) A person who is older than another; one more advanced in life.

(6):

(n.) One older in office, or whose entrance upon office was anterior to that of another; one prior in grade.

Bibliography Information
Webster, Noah. Entry for 'Senior'. Noah Webster's American Dictionary. https://www.studylight.org/dictionaries/eng/web/s/senior.html. 1828.

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