ISO 4378-2:2009 gives the most commonly used terms relating to friction and wear of plain bearings with their definitions and classification. For some terms and word-combinations, their short forms are given, which can be used where they are unambiguous. Self-explanatory terms are given without definitions. In addition to terms used in English and French, two of the three official ISO languages, ISO 4378-2:2009 gives the equivalent terms in German; these are published under the responsibility of the member body for German (DIN), and are given for information only. Only the terms and definitions given in the official languages can be considered as ISO terms and definitions.