Diver is an ambiguous term with multiple possible uses.
The term diver typically refers to a character engaged in the act of diving underwater, usually with supportive equipment such as a breathing apparatus.

It can also refer to:

General

• scuba_diver - see above
• diver propulsion vehicle - also known as an "underwater scooter"
• skydiver - a character leaping from a high point in the atmosphere, using a parachute to control their descent

Species

• loon - the common name of this bird in British English is "diver"

Characters

• skye_diver
• diver_(abzu)

Copyrights

• gundam build divers
• gundam build divers re:rise

Artists

• diver_(artist) - diaperfur artist