noun

• A member of a supposed prehistoric race that lived in caves or holes, a caveman.
• (by extension) Anything that lives underground.
• A reclusive, reactionary or out-of-date person, especially if brutish.
• The Eurasian wren, Troglodytes troglodytes.
• (computing) A person who chooses not to keep up-to-date with the latest software and hardware.