portion vs subpart

portion and subpart both are nouns.

Word	Noun	Adjective	Verb	Adverb
portion	Yes	No	Yes	No
subpart	Yes	No	No	No

As nouns, subpart is a hyponym of portion; that is, subpart is a word with a more specific, narrower meaning than portion:

portion (noun)	subpart (noun)
the allotment of some amount by dividing something	a part of a part
something less than the whole of a human artifact
an individual quantity of food or drink taken as part of a meal
assets belonging to or due to or contributed by an individual person or group
money or property brought by a woman to her husband at marriage
something determined in relation to something that includes it
your overall circumstances or condition in life (including everything that happens to you)

portion (verb)	subpart (verb)
give out