Definition of junior
- junior Adjective Younger.
- junior Adjective Of or pertaining to a third academic year in a high school or university.
- junior Adjective Low in rank; having a subordinate role, job, or situation.
- junior Noun A younger person.
- junior Noun A third-year student at a high school or university.
- junior Noun A name suffix used after a son's name when his father has the same name. Abbreviation: Jr.