In the context of object-oriented formalism, stereotypes are presented as a new means for user-defined extensions of the Unified Modeling Language (UML). Unfortunately, the stereotypes syntax and semantics vary depending on the proposed extensions and it is not easy to propose a complete formalization of this mechanism. This is the reason why this paper tries to identify and formalize a pertinent set of stereotypes called stereotypes for type specification. This category of stereotypes was intuitively or implicitly presented in several works and has been experimented in different modeling methods, especially in the field of Geographic Information System (GIS). This paper proposes a complete study of this class of stereotypes and discusses the interest of their applications. Numerous examples will be presented in the field of GIS.