IPA: /ɔˈtʌmnəl/
KK: /ɔˈtʌmnəl/
Relating to the season of autumn, which is the time of year when leaves change color and fall from trees.
The autumnal leaves created a beautiful carpet of colors on the ground.
Autumnal is formed from "autumnus" (meaning autumn) and "-al" (meaning relating to). The word describes something that is related to or characteristic of the autumn season.
Think of the word 'autumn' to remember that 'autumnal' refers to things related to the autumn season.