IPA: //ˈsʌbˌaɪtəm//
KK: /sʌbˈaɪtəm/
A smaller item that is part of a larger item or category.
In the report, each subitem is listed under its main category.
Subitem → It is formed from "sub-" (meaning under or below) and "item" (from Latin "item", meaning also or likewise). The word "subitem" refers to an item that is under or a part of a larger item or category.
Think of something that is 'under' ('sub-') a main item — that's why a subitem is a part of a larger whole.