/seen"yeuhr/ , adj.
1. older or elder (usually designating the older of two men bearing the same name, as a father whose son is named after him, often written as Sr. or sr. following the name): I would like to see the senior Mr. Hansen Mr. Edward Andrew Hansen, Sr. Cf. junior (def. 1).
2. of earlier appointment or admission, as to an office, status, or rank: a senior partner.
3. of higher or the highest rank or standing.
4. (in American schools, colleges, and universities) of or pertaining to students in their final year or to their class.
5. (in certain American colleges and universities) of or pertaining to the final two years of education, during which a student specializes in a certain field of study.
6. of, for, or pertaining to a senior citizen or senior citizens as a group: senior discounts on local bus fares.
7. of earlier date; prior to: His appointment is senior to mine by a year.
8. Finance. having a claim on payments, assets, dividends, or the like prior to other creditors, mortgages, stockholders, etc.
n.
9. a person who is older than another.
10. a person of higher rank or standing than another, esp. by virtue of longer service.
11. (in the U.S.) a student in the final year at a high school, preparatory school, college, or university.
12. a fellow holding senior rank in a college at an English university.
13. a senior citizen.
14. ( cap. ) a member of the Girl Scouts from 14 through 17 years of age.
[ 1350-1400; ME sen ( ex ) old, old man + -ior comp. adj. suffix ]