1. one of four children born at the same birth
2. a group or set of four similar things

Examples

• The hospital prepared four cribs for the expected quadruplets.
• Raising quadruplets requires enormous patience and energy.
• The quadruplets celebrated their first birthday together.
• She gave birth to healthy quadruplets after a difficult pregnancy.
• The musical piece featured a quadruplet of sixteenth notes.
• The scientist observed a quadruplet of similar specimens.
• Each quadruplet had a distinct personality despite being identical.