This part of ISO 1122 concerns the part of the international vocabulary of gears which is devoted solely to geometrical definitions. It gives, for each of the geometrical terms relative to gears, a standard definition which will be valid internationally, the corresponding term in each language being chosen as far as possible in such a way as to directly reflect the meaning of the definition. NOTE — Since the choice of corresponding terms can only be partially fulfilled in any particular language, due to the necessity of respecting certain established conventions, it is advisable, as far as translation into other languages is concerned, to refer always to the meaning of the definition itself, rather than to a simple transposition of the original term.