​Glossary of terms and acronyms The definitions and acronyms included in this glossary originate from the Business Practice Manual for Definitions and Acronyms.  The symbols [T] and [M] indicate the definition was obtained from the ISO Tariff Appendix A, Master Definitions Supplement. The symbol [M] definitions were modified slightly for consistency with the business practice manuals and to improve definition accuracy.  Please refer to the Business Practice Manual for Definitions and Acronyms for the most up to date list of terms. Updated 11/13/2015Filter by letter of the alphabet, acronym or term name.