To descend means to move downward, to go from a higher place to a lower one. When you descend a staircase, you walk down it. When an airplane descends for landing, it lowers toward the runway. Mountain climbers who reach the summit still need to descend safely back to base camp.

The word carries a sense of controlled movement downward, not falling or tumbling. A spelunker descends into a cave using ropes and careful footing. An elevator descends to the lobby. Even abstract things can descend: when darkness descends at sunset, it seems to settle over everything.

You might also hear about people being descended from someone, which means that person is their ancestor. If you're descended from Irish immigrants, they're part of your family tree. This usage connects to the idea of coming down through generations, like branches descending from a tree trunk.

The opposite of descend is ascend, which means to go upward.