By "preclassification" is meant a first stage of classification, for purposes of internal application (file) routing and distribution, whereby the subject of the claimed invention (or the invention first claimed, if there is more than one) is broadly identified by means of the appropriate classification symbols.

By "IPC classification" is meant the assigning of the appropriate classification symbols according to the International Patent Classification (IPC), published by WIPO. See the WIPO website for the IPC edition in force, and the "Guide to the IPC", which sets forth principles and rules of classification.

By "CPC classification" is meant the assigning of the appropriate classification symbols according to the Cooperative Patent Classification (CPC), published by the EPO and the USPTO. See the CPC website for the CPC edition in force, and the "Guide to the CPC", which complements the "Guide to the IPC" in that it covers the distinguishing features of the CPC compared to the IPC.