What is the meaning of Autumn?

Traditionally the third of the four seasons, when deciduous trees lose their leaves; typically regarded as being from September 24 to December 22 in parts of the Northern Hemisphere, and the months of March, April and May in the Southern Hemisphere.

The time period when someone or something is past its prime.

A person with relatively dark hair and a warm skin tone, seen as best suited to certain colours in clothing.

To spend the autumn (in a particular place).

To undergo the changes associated with autumn, such as leaves changing color and falling from trees.

Source: wiktionary.org