1. active or occurring during the night
2. relating to or happening at night

Examples

• Owls are nocturnal birds that hunt at night.
• The nocturnal sounds of crickets filled the air.
• Many nocturnal animals have excellent night vision.
• She enjoyed taking nocturnal walks through the quiet streets.
• Bats are nocturnal creatures that sleep during the day.
• The nocturnal shift at the hospital runs from 11 PM to 7 AM.
• Nocturnal blooming flowers open only after sunset.