senior

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Of or being the older of two, especially the older of two persons having the same name, as father and son.
2. adj. Of or relating to senior citizens. See Usage Note at old.
3. adj. Being in a position, rank, or grade above others of the same set or class: a senior officer; the senior ship in the battle group.
4. adj. Having precedence in making certain decisions.
5. adj. Of or relating to the fourth and last year of high school or college: our senior class.
6. n. A person who is older than another: She is eight years my senior.
7. n. A senior citizen.
8. n. One that is of a higher position, rank, or grade than another in the same set or class.
9. n. A student in the fourth year of high school or college.

Century Dictionary and Cyclopedia

1. Older; elder: when following a personal name, as John Smith, senior (usually abbreviated Sr. or Sen.), it denotes the older of two persons in one family or community of that name.
2. 2. Older in office or service: as, a senior judge, colonel, etc.
3. 3. Belonging or pertaining to the fourth or last year of the curriculum of an American college, seminary, or other institution: as, the senior class.
4. n. A person who is older than another; one more advanced in life; an elder.
5. n. One who is older in office or service, or whose first entrance upon such office or service was anterior to that of another.
6. n. 3. An aged person; one of the older inhabitants.
7. n. In the universities of England, one of the older fellows of a college. See seniority, 3.
8. n. In the United States, a student in the fourth year of the curriculum in colleges or seminaries; also, one in the last or most advanced year in certain professional schools; by extension, a student in the most advanced class in various institutions.

Wiktionary

1. adj. Older; superior
2. adj. Higher in rank within a publicly traded company or other organization.
3. adj. of or pertaining to a student's final academic year at a high school (twelfth grade) or university.

GNU Webster's 1913

1. adj. More advanced than another in age; prior in age; elder; hence, more advanced in dignity, rank, or office; superior.
2. adj. Belonging to the final year of the regular course in American colleges, or in professional schools.
3. n. A person who is older than another; one more advanced in life.
4. n. One older in office, or whose entrance upon office was anterior to that of another; one prior in grade.
5. n. An aged person; an older.
6. 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.

WordNet 3.0

1. n. an undergraduate student during the year preceding graduation
2. adj. older; higher in rank; longer in length of tenure or service
3. adj. advanced in years; (`aged' is pronounced as two syllables)
4. adj. used of the fourth and final year in United States high school or college
5. n. a person who is older than you are