A subproject is a project which is governed through another project.
Collectives often delegate the governance of subprojects to a variety of official roles or posts within the collectives, including shared posts (teams). Also, post-holding agents often self-organize by creating their own subprojects. Sustainable governance and project management ultimately require clear distinction between the subprojects of collectives and of the projects and roles within them.
Project and subproject relationships can extend indefinitely throughout the hierarchical levels of a large collective.