- Regular Expression
A sequence of characters that represents a pattern.
- Regular Expression Engine
A specific implementation of regular expressions used by a specific programming language.
- Literal Character
A character in a regular expression that matches itself.
- Character Class
A set of characters enclosed in brackets. It matches any one of the characters in the set.
- Metacharacter (also called “Special Character”)
A character in a regular expression that does not match itself, but instead has a special role in specifying the overall pattern.