This part of ISO 1998 consists of a list of equivalent English and French terms, with the corresponding definitions, in use in the petroleum industry and that are not definitely relevant to one of the six categories of other parts of this International Standard. ISO 1998 is intended to cover the purposes of the part of the petroleum industry dealing with crude oils and petroleum products, that means all related operations arising from the production field to the final user. It is not intended to cover either petroleum equipment, or any operation in the field. However, some pieces of equipment or some operations of exploration and production are defined. The corresponding terms were introduced only when they appear in a definition of a product or process and when their definition was found necessary for understanding or for avoiding any ambiguity. Where a terminology of petroleum equipment is needed, it corresponds to the scope of ISO/TC 67, Materials, equipment and offshore structures for petroleum and natural gas industries.