A hypergeometric series is a type of mathematical series that has a specific form and is found to be useful in a variety of mathematical applications. There are several synonyms for the term hypergeometric series, including hypergeometric function, Gauss' hypergeometric function, and Heine's hypergeometric function. Other related terms include Jacobi's hypergeometric function, Appell's hypergeometric function, and Legendre's hypergeometric function. These terms all refer to specific variations of the hypergeometric series that have been extensively studied and found to have important mathematical properties. The study of hypergeometric series and their related functions is an active area of mathematical research with numerous applications in physics, engineering, and other scientific fields.