IPA: /sʌbˈprɒdʒɛkt/
KK: /sʌbˈprɒdʒɛkt/
A smaller project that is part of a larger project.
The team is working on a subproject to improve the software's user interface.
Subproject → It is formed from "sub-" (meaning under or below) and "project" (from Latin "proicere", meaning to throw forward). A subproject refers to a project that is part of a larger project, thus it is 'under' the main project.
Think of a project that is 'under' a larger one — 'sub-' means under, and 'project' means to throw forward or plan.