Emily Dickinson Lexicon

SEN-IOR, n. [see'nyor.]

1. A person who is older than another; one more advanced in life.
2. One that is older in office, or one whose first entrance upon an office was anterior to that of another. Thus senator or counselor of sixty years of age, often has a senior who is not fifty years of age.
3. An aged person; one of the oldest inhabitants. A senior of the place replies. – Dryden.