秋 (あき) means "autumn" or "fall," the season after summer. It's known for cooler weather and colorful leaves. You can say 秋は紅葉が綺麗です (Aki wa kōyō ga kirei desu), meaning "Autumn leaves are beautiful in the fall."

秋（あき）は夏の後で、涼しくなる季節です。「秋は好きですか」のように使います。