A crescendo is a gradual increase in loudness in music. When an orchestra plays a crescendo, the sound starts soft and builds steadily until it reaches a powerful, dramatic volume. Imagine a wave rolling toward shore, starting as a gentle ripple far out in the ocean and growing larger and louder as it approaches the beach.

Musicians see crescendo marked in their sheet music with a long symbol that looks like a sideways “V” opening to the right, or sometimes with the abbreviation cresc. A conductor might sweep their arms upward to guide the musicians through a crescendo, signaling them to play with increasing intensity.

Outside of music, people use crescendo to describe anything that builds in intensity. A crowd's excitement might reach a crescendo when a basketball player lines up a game-winning shot. An argument might build to a crescendo before someone finally storms out of the room. A thunderstorm might arrive in a crescendo of wind and rain.

People sometimes use crescendo to mean the loud peak itself, but it can also refer to the building process. The journey from quiet to loud is a crescendo, and that final powerful moment at the end is the peak.