subtotal vs amount

subtotal and amount both are nouns.

Word	Noun	Adjective	Verb	Adverb
subtotal	Yes	No	No	No
amount	Yes	No	Yes	No

As nouns, amount is a hypernym of subtotal; that is, amount is a word with a broader meaning than subtotal:

Other hypernyms of subtotal include sum, total.

subtotal (noun)	amount (noun)
the sum of part of a group of numbers	how much there is or how many there are of something that you can quantify
	the relative magnitude of something with reference to a criterion
	a quantity obtained by the addition of a group of numbers
	a quantity of money

subtotal (verb)	amount (verb)
	to measure up to in kind or quality
	add up in number or quantity
	be tantamount or equivalent to