1. people who are not married or in romantic relationships
2. single children born alone rather than as twins or multiples
Usage: medical
3. individual items that exist alone or separately

Examples

• The dating app is designed specifically for singletons looking for relationships.
• Many singletons enjoy the freedom of living alone.
• The study compared the development of singletons versus twins.
• She was born a singleton after her parents had twins.
• The store sells singletons of popular items that are usually sold in pairs.
• In bridge, having too many singletons can make your hand difficult to play.
• The collector was interested in singletons rather than complete sets.