Transient means lasting only a short time or passing through without staying. A transient feeling of sadness might wash over you when saying goodbye to a friend, but it fades as you get distracted by other things. Morning dew on grass is transient: it disappears as soon as the sun warms the air.

The word often describes things that come and go rather than settling in permanently. A transient population might refer to college students who live in a town for four years but then move away, unlike the families who've lived there for generations. Migrating birds are transient visitors to a region, stopping briefly during their journey before continuing on.

Scientists use the word to describe temporary phenomena. A transient electrical surge lasts only milliseconds. Astronomers study transient events like supernovas that flare up brilliantly and then fade.

As a noun, a transient is a person who stays in a place only briefly, without settling there.

When something is transient, you know it won't last, which can make it feel either precious (like a beautiful sunset) or bearable (like an uncomfortable situation you know will end soon).