紅葉
こうよう · kouyou · JLPT N2 · noun
colors
🍁🍂 紅 (red) + 葉 (leaf) = red leaves, the autumn fall colors of foliage
The two characters combine literally: 紅 means red and 葉 means leaf. Together they name the reds and yellows of autumn foliage, which is why 紅葉 is a seasonal word.
もみじ · momiji · JLPT N2 · noun
maple
🍁 紅 (red) + 葉 (leaf) = red leaves, the Japanese word for maple
Japanese uses the same word for the maple tree and its red autumn foliage. Both characters are common, so the compound is easy to decode.