singleton

中文： 单例

1. A playing card that is the only one of its suit in a hand, especially at bridge.
2. A hand containing only one card of a certain suit.
3. A single object, especially one of a group.
4. A class that may not be instantiated more than once, i.e. that implements the singleton design pattern.
5. A set with exactly one element.
6. A child or animal that is born singly, not as a twin or other multiple birth. · singleton preterm birth
7. A person without a romantic partner.
8. A person without a dissociative identity.

复数 singletons