IEC GUIDE 108:2019 defines rules for dealing with horizontal functions and horizontal publications. This Guide is to be used in conjunction with the ISO/IEC Directives and with the aspect specific Guides. The fundamental concept of a horizontal publication is that it is an international publication (not a TS or a PAS) that is widely applicable and to be used by all relevant committees and that has undergone an enhanced approval process as described in this document. In this Guide: – the term "committees" includes technical committees, project committees, subcommittees and systems committees. – the term "publication" includes International Standard, Technical Report, Technical Specification, Publicly Available Specification and Guide. – the term "product" is used to refer to individual products, processes, services and combinations thereof, commonly known as "systems".