This is the 4981st most frequent Japanese word.
紅
"紅" means "crimson" or "deep red" in English.
Here, '紅' is used as part of '紅葉' which means autumn leaves, indicating the red color they display.
紅葉が秋に美しく色づく。
The autumn leaves turn beautifully red in fall.
In this sentence, '紅' directly expresses the red color in the context of lipstick.
彼女は紅の口紅を付けている。
She is wearing red lipstick.
'紅茶' literally means 'red tea', utilizing '紅' to describe the reddish-brown color of black tea.