The derived word ‘nirUpaNaM’ (proof) is derived from the idea that proof is nothing but a demonstration of the true nature.
However when we say ‘rUpaM’, our mind does not take it to be of an inert nature but something which has life.
For instance when we say “the musician brought forth the ‘rUpaM’ of the rAga very well” we actually feel that the rAga itself is a living soul.
In fact we do that to every art form.
Science is never spoken of that way.
Do we ever say “The Professor brought forth very well the form of Physics”? The reason is that Science is not thought of as a living thing like Art.
I am saying all this because whenever we speak of the nature of something in terms of ‘rUpa’, there is always some connection with the concept of life.