When you want to indicate that something is a component or a constituent of a larger entity, you may use expressions like "inclusion in," "belonging to," or "being a portion of." You could also say that something is "comprised in," "included within," or "encompassed by" another piece of something. Other options are "forming a fraction of," "constituting an element of," or "making up a segment of" a larger whole. When trying to add diversity to your writing, finding synonyms for commonly-used phrases like "forming a part of" can be helpful in avoiding unnecessary repetition and making your piece more engaging.