Autumn in Chinese / Japanese...

秋 is the word/character used to describe the Autumn or Fall season in Chinese and Japanese.

See Also:  Winter | Spring | Summer | Four Seasons

This refers to the red autumnal leaves or autumn colors.

You can also say fall colors, leaves changing color, or leaves turning red.

The characters themselves mean red leaves. The rest of the meaning is implied and understood to include autumn and the fact that they are changing.

春夏秋冬 is one way to express “The Four Seasons “ or “All Year Round “.

The characters here represent Spring, Summer, Autumn (Fall), and Winter.

四季 is the 2-character way to say “Four Seasons.”

四季 literally means “4” and “seasons.”

一日千秋 is a Japanese and Chinese proverb about missing someone.

一日千秋 is often used to express how hard it is to wait for someone's return or to be away from someone.

Some will translate this as “one day feels like a very long time” or “waiting for someone (something) is hard.”

You might see this romanized as a single word, Ichijitsusenshuu, or as “Ichijitsu Senshuu” from Japanese.
If you break down the characters one-by-one, we get:
一 = one/a
日 = day/sun (can also represent time or date)
千 = 1000/thousand
秋 = autumn/fall

Together, 千秋 can mean “autumn comes thousand times” (or 1000 years). It can also be read as 1000 periods of time.
However, it relays the idea of heartache as you wait for someone you miss.