twilight

A celestial glow whose intensity increases progressively before sunrise (morning twilight) and decreases after sunset (evening twilight). That ambient luminosity is caused by the sun, already hidden below the horizon but close to it. Its duration varies depending on the day of the year and the observer's latitude. Morning twilight goes by other names such as dawn or daybreak, while evening twilight is also referred to as dusk, sunset, or nightfall. The word lubrican is a synonym for both.