1. Day (noun): The 24-hour period from midnight to midnight, constituting a full rotation of the Earth. 2. Day (noun): The period of time during which the sun is visible, typically from sunrise to sunset. 3. Day (noun): A specific date or occasion, such as a holiday or significant event. 4. Day (noun): A period […] The post Day: Definition, Meaning, and Examples appeared first on US Dictionary.