Shade and shade exist. The word "shade" has no prefix "grass", which means it doesn't really mean trees. The definition of the word "Yin" in the dictionary is: the shadow formed by the light being blocked by something. "Tree" is interpreted as the original meaning: trees. So these two words can be understood as: the shadow formed by the light being blocked by trees. The word "shadow" of "shadow" has the prefix "grass", which means it is related to the entity tree. Below is the word "Yin", which means that "Yin" is related to "Yin". "Tree" still means: tree. From this point of view, "Yin" is shade, that is, it is blocked by big trees, and "Yin" is simply the shadow that big trees cast on the ground in the sun.