What is the Official Catchword Index?
The Official Catchword Index helps the users to find a starting point in the classification scheme by browsing a list of catchwords. It offers about 20,000 entries consisting of short technical terms/keywords which refer the user to an appropriate classification place. Try to use generic topics when you are looking for a particular topic. If you did not find “Bacterial leaching”, try “Hydrometallurgy”, and if you did not find it, try “Metallurgy”. For the reformed IPC, there is only one version of the Official Catchword Index for both the core and advanced levels. However, symbols belonging to the advanced level only are distinguishable from symbols existing in both levels. It will be updated with each new version of the core level. The Official Catchword Index is available in English and French online via the Internet presentation of the IPC (see the corresponding tab in the top line). The German Patent and Trade Mark Office has prepared a more detailed version of a Catchword Index in
