In the northern hemisphere, October is the season of autumn foliage, when a myriad of green leaves turn yellow, orange, or red, depending on their species and the coldness of the environment. The term ‘autumn’ can be used interchangeably with ‘fall,’ which is less formal. The term ‘foliage’ comes from a French medieval word, ‘feuillage,’ meaning the leaves of trees.
Like the other three seasons, ‘autumn’ and ‘fall’ do not need to be capitalized unless they appear at the beginning of a sentence. Meanwhile, the term ‘autumntime’ is rarely used despite its existence in dictionaries.