This chapter explains notational terms and conventions used throughout the MPI-2 document, some of the choices that have been made, and the rationale behind those choices. It is similar to the MPI-1 Terms and Conventions chapter but differs in some major and minor ways. Some of the major areas of difference are the naming conventions, some semantic definitions, file objects, Fortran 90 vs Fortran 77, C++, processes, and interaction with signals.