A bachelor is an unmarried man, especially one who has never been married. The word usually describes adult men who are old enough to be married but haven't chosen to yet. You might hear someone say, “My uncle lived as a bachelor until he was forty,” meaning he stayed single until then.

Bachelor can also describe certain academic degrees. A bachelor's degree (like a Bachelor of Arts or Bachelor of Science) is what you earn when you complete a college program, often around four years long.

People sometimes use bachelor playfully to describe someone who lives alone and makes their own choices about how to run their household. A bachelor apartment or bachelor pad is a small living space designed for one person. The word can carry a sense of independence: bachelors cook their own meals, do their own laundry, and keep their own schedules without having to coordinate with a spouse.