IPA: /ˈsʌbˌpɑrt/
KK: /sʌbˈpɑrt/
A smaller part of a larger part; a component that is included within another component.
The engine has several subparts that need to be assembled carefully.
Subpart → It is formed from "sub-" (meaning under or below) and "part" (from Latin "partem", meaning a piece or portion). The word "subpart" refers to a piece or portion that is under or part of a larger whole.
Think of something that is a 'piece' ('part') that is 'under' ('sub-') a larger structure — that's what a subpart is.