When discussing sets, subsets are an important concept to understand. A subset refers to a portion of a set that contains certain elements but not others. There are several synonyms for the term subset, including subcollection, subset group, subset class, and part set. These terms are often used interchangeably to describe a smaller set of elements that belong to a larger set. It is important to note that subsets can be formed from any set, including infinite sets, and that they are a key element in mathematical theory. By studying subsets, researchers can better understand the relationships between different sets and their elements.