I. ˈsē-nyər noun
Etymology: Middle English, from Latin, from senior, adjective
Date: 14th century
1. : a person older than another
five years my senior
2.
a. : a person with higher standing or rank
b. : a senior fellow of a college at an English university
c. : a student in the year preceding graduation from a school of secondary or higher level
3. capitalized : a member of a program of the Girl Scouts for girls in the 9th through 12th grades in school
4. : senior citizen
II. adjective
Etymology: Middle English, from Latin, older, elder, comparative of sen-, senex old; akin to Gothic sineigs old, Greek henos
Date: 14th century
1. : of prior birth, establishment, or enrollment — often used to distinguish a father with the same given name as his son
2. : higher ranking : superior
senior officers
3. : of, relating to, or intended for seniors
a senior center
4. : having a claim on corporate assets and income prior to other securities