I'm not sure what the question is asking? But, a part is a fraction of a whole. For instance: 1/2 is a half of a whole, or 50% of 100%
A part to whole is, essentially, a ratio. 2:10 is a ratio---it could also be 2(the part) to 10(the whole). The part is how much the part is in comparison to the whole-1/2 could be the part, while 1 is the whole.
vinculum unitatis - das Band der Einheit (bond(s) of unity).
A proper fraction can represent a comparison between a part (the numerator) and the whole (the denominator).
Comparison is a noun.
The word 'comparison' is a noun.
The part of an experiment that's the standard for comparison is called the Control
It is a vinculum