You used the wrong definition. Try definition 4, "a value or size of a series of values or sizes (as of money)
Look at the matter less in terms of religious denomination and look at it in terms of currency denomination. You’ve got one-dollar bills and five-dollar bills and twenty-dollar bills, etc. These bills are called denominations. But these bills are only paper. They have no intrinsic value. We recognize them as valuable only because behind these flimsy pieces of paper is a vault somewhere full of something that is actually valuable. It used to be gold.
The Catholic Church is not a denomination, it is the gold standard that has real intrinsic value The value of Protestant denominations stems from this gold standard. For example, Protestant denominations believe in the Bible, because the Catholic Church gave the world the Bible. Protestant denominations believe in the Trinity, because the Catholic Church defined the Trinity. Need I go on?
So to reiterate, no the Catholic Church is not a denomination.