We called light as day and dark as night. Why?

We can see everything in the daytime. Everything looks clear. You will hardly mistake anything in the daytime.

We hardly see anything in the night time, unless we have some source of light which probably will not be enough to reveal the true form of the object. Not everything is clear. Sometime, things look good, but it's not. And sometime, things look bad, but it's good.

Day and Night. Light and Dark.