Actually the EPO does not build databases with technical dictionaries. However, patent documents are classified by technical domains in two main hierarchical classification systems, the international patent classification (IPC)
and the cooperative patent classification (CPC)
systems. These classification systems help many patent searchers to specify their patent searches.
Maybe these classification systems could help you to find classifications with definitions that would distinguish the two concepts mentioned (“caul plate” and “mould face”). If you need further information about patent classification systems, please check WIPO International Classifications
Cooperative Patent Classification
To search for relevant classification symbols and corresponding definitions, you can use the classification search form of Espacenet
and enter, on one side, e.g. the keywords “caul plate”, and, on the other side, e.g. the keywords “mould face”. CPC being an extension of IPC, i.e. with additional definitions, searching for CPC will also search for IPC.
The system works in the following way: It analyses all patent documents available in the EPO worldwide patent bibliographic database which contain the searched keywords in their title or abstract. It then retrieves and displays a list of the mostly used classification symbols in these documents. Once you have the displayed list of classification symbols, you will then need to look at the different corresponding definitions and decide which classification symbol(s)/definition(s) could be relevant for you. Please note that, if you click on a classification symbol in the list, Espacenet will display classification symbols with more precise and narrow definitions (“hierarchical classification system”).