a rnadmo (random) thought

Green. Red. Why is it named so? Why is this particular shade called green or red? Same goes to Blue, Yellow, Brown, White, Black, etc. Why whoever named these colours didn't call them something else instead? And why have all living humans acquiesced to use these names to identify these colours? ...Also, not just the colours. Same goes to that broad piece of plank with four legs which we call Table, or its loyal company we call Chair. From the tiniest little gadget we can find in our household to the many enormous structures that exist today, why are they all named so? I wonder..