Apparently, meanings come from context. ie the red of an apple can be different from the same red shade as blood. The difference is via meanings assigned to blood and apples which provide variations in meanings.
Colours however, are made from absence (as in the object does not have a colour), a reflection (of the colour being perceived), and the absorption of all other colours. The green of a leaf is not what the leaf’s colour might be, and indeed not what it absorbs, its a reflection.
Would it need some other entity to be seen? Would it not be green if there was some other than human being to perceive?