The recommendations in This Standard apply particularly to fits between cylindrical parts, briefly designated as 'holes' and 'shafts', in which case the term 'size' refers to the diameter of the mating parts. The data may also be applied in appropriate cases, by suitable selection of the grades of allowance and tolerances, to fits between other than cylindrical mating parts, in which case the 'size' refers to a length, width or other dimension instead of to a diameter.