Autumnal means having to do with autumn, or having qualities that remind you of that season. When leaves turn brilliant shades of red, orange, and gold, that's an autumnal display. When the air gets crisp and you need a jacket in the morning, that's an autumnal chill.

Autumnal describes more than just the calendar: it captures the particular feeling of autumn. An autumnal color might be warm rust orange or deep burgundy. An autumnal afternoon might feature slanting golden sunlight and the smell of wood smoke.

Writers use autumnal to describe things that share autumn's character: a sense of ripeness, harvest, and gentle decline. You might describe a person in their later years as being in the autumnal phase of life, suggesting maturity and wisdom rather than the fresh energy of youth. A poem about change and letting go might have an autumnal mood. When something is autumnal, it carries that bittersweet quality of beauty mixed with endings, like watching leaves fall and appreciating their colors one last time.