Regular is an adjective with multiple meanings:
1. Happening or doing something frequently or at fixed intervals: "I'm a regular customer at this cafe."
2. Normal, usual, or standard: "Just give me the regular size, please."
3. Following a rule or pattern: "The verb conjugation follows a regular pattern."
4. In military context: belonging to the permanent professional army
5. In geometry: having all sides and angles equal
6. In North American English: of medium size (e.g., regular coffee)