This International Standard relates to twist drills and shows the various types in common use and associated geometrical definitions. Terms and definitions have been chosen with respect to the tool-in-hand system which has been defined in ISO 3002/1. NOTE — In addition to terms given in the three official ISO languages (English, French and Russian), this International Standard gives the equivalent terms in the German, Italian and Dutch languages; these have been included at the request of ISO Technical Committee 29 and are published under the responsibility of the member bodies for Germany (DIN), Italy (UNI) and the Netherlands (NNI). However, only the terms given in the official languages can be considered as ISO terms.