CPC stands for Cooperative Patent Classification and is one of the categorisation systems for patents. CPCs are used in 39 countries and are administered in a joint collaboration between the European Patent Office (EPO) and the United States Patent and Trademark Office (USPTO) and are used to classify the content of patents in a uniform manner. It is a hierarchical system made up of letters and numbers, which allows you to identify patents in a specific field of technology. For instance, the category A is labeled "Human Necessities", within category A there are then 15 subcategories. Those subcategories then have sub-sub-categories, sub-sub-sub categories and so on. These go all the way down to A01B1/02, for instance, with each section or level of the CPC becoming more and more specific, that now referring to "Spades; Shovels".
With foreign patents and patents that are written in misleading or uncommon jargon, they can be very difficult to find using a keyword search. Searching by CPCs ensures that you will capture all technologies within a specific field, regardless of the terminology used.
Using CPCs may be preferred to IPCs since CPCs are more up to date than IPCs. However, IPCs are used in a lot more countries than CPCs. You can find out more about IPCs here: What is an IPC and why it is important to my search?
PatSnap has a glossary of all CPCs which you can find HERE.