Definitions

1. noun

A suffix used to indicate that the person to whom it is attached is the son or younger relative of someone with the same name.

“John Smith Jr. is the son of John Smith.”

2. adjective

Youthful or younger than another person with the same name.

“John Smith Jr. is often confused with his father, John Smith Sr.”

3. abbreviation

Junior, used in academic or professional titles.

“John Smith Jr., Ph.D.”