junior

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Used to distinguish a son from his father when they have the same given name.
• adjective Intended for or including youthful persons.
• adjective Lower in rank or shorter in length of tenure.
• adjective Of, for, or constituting students in the third year of a US high school or college.
• adjective Lesser in scale than the usual.
• noun A person who is younger than another.
• noun A person lesser in rank or time of participation or service; subordinate.
• noun A student in the third year of a US high school or college.
• noun A class of clothing sizes for girls and slender women.

from The Century Dictionary.

• Younger; not as old as another.
• Younger or lower in standing, as in a profession, especially the bar: as, a junior counsel; a junior partner in a firm or company.
• In American colleges and schools, pertaining to the third year of the course, the next below the senior or last year; in institutions having a three years' course, usually pertaining to the first year (the second being called the middle year): as, the junior class; junior students.
• noun A person younger than another.
• noun One of less experience or inferior standing in his profession than another, who is called his senior; one employed as the subordinate of another, especially at the bar.
• noun In American colleges and seminaries, a member of the junior class; a student in the junior year.

from the GNU version of the Collaborative International Dictionary of English.

• noun A younger person.
• noun One of a lower or later standing; specifically, in American colleges and four-year high schools, one in the third year of his course, one in the fourth or final year being designated a senior; in some seminaries, one in the first year, in others, one in the second year, of a three years' course.
• adjective Less advanced in age than another; younger. Abbreviated Jr.
• adjective Lower in standing or in rank, or having entered later into a position or office
• adjective Composed of juniors, whether younger or a lower standing; ; of or pertaining to juniors or to a junior class. See Junior, n., 2.
• adjective Belonging to a younger person, or an earlier time of life.
• adjective of or relating to the third year of a four-year term; -- used of the third or next to final year in a U. S. high school or college. See junior{2}, n..

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective not comparable Younger.
• adjective not comparable Of or pertaining to a third academic year in a four-year high school (eleventh grade) or university.
• adjective comparable Low in rank; having a subordinate role, job, or situation.
• noun A younger person.
• noun A third-year student at a high school or university.
• noun A name suffix used after a son's name when his father has the same name. Abbreviation: Jr.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective younger; lower in rank; shorter in length of tenure or service
• adjective used of the third or next to final year in United States high school or college
• noun a son who has the same first name as his father
• noun a third-year undergraduate
• noun term of address for a disrespectful and annoying male
• adjective including or intended for youthful persons
• noun the younger of two persons