Slumber means to sleep, especially peacefully or lightly. When you slumber, you rest in a calm, gentle way. A baby slumbers in a crib, and you might slumber on a lazy Saturday morning when there's nowhere you need to be.

The word has a softer, quieter feeling than just “sleep.” While you might crash into bed exhausted after a long day, slumber suggests something more tranquil and undisturbed. It's the kind of sleep where you look peaceful and comfortable, not restless or troubled.

You'll often see slumber in stories and poems because it sounds more poetic than ordinary “sleep.” When Sleeping Beauty falls under a curse, she enters a deep slumber that lasts for years. A slumber party (or sleepover) gets its name because friends gather to sleep at someone's house, though they usually stay up late talking and laughing instead of actually slumbering.

The word can also describe something that seems asleep or inactive. A town might slumber quietly in the early morning hours before anyone wakes up, or a volcano might slumber for centuries before erupting again.