Unicorns and Units

It is understood that "units" are the labeling of quantities of dimensions. Dimensions are tangible, and empirical. Yet are they not also absract? That is to say, can I not "imagine" the length, and width of this, or that.

Such as unicorns....they are entirely absract. Yet cannot I imagine a small unicorn. A tall unicorn. A fat unicorn....lol...

Therefore "space", "dimensions", and units can all exist as abstractions.

So then why do "absract numbers" not contain units, or dimensions? Just as concrete numbers do.

The difference of course is that the unit for absract numbers is...absract. While the units for concrete numbers is...concrete.

So then while all numbers are defined as numerical quantities...except for zero. Which is defined as the absence of a numerical quantity. Zero is not absent a dimensional unit quantity.