This part of ISO 14132 gives terms, definitions and letter symbols of common notions that are typical for all types of telescopic systems. The alphabetical indexes of terms in English, French, Russian and German that are common for all published parts of ISO 14132 are published in this part of ISO 14132. The definitions may be changed, if required, by introducing derivative attributes into them, revealing the meanings of the terms used, showing the objects covered by the scope of the notion being defined. These changes shall not affect the scope and contents of this part of ISO 14132.