What Does Compatible Cartridge Mean?

A compatible cartridge is an ink cartridge for inkjet printers made by a third party. It is designed to fit a printer in place of cartridges made by the printer manufacturer. The use of these cartridges may violate the warranties of the printers, but a U.S. court case has found that they do not violate the Digital Millennium Copyright Act (DMCA).

Techopedia Explains Compatible Cartridge

Compatible cartridges are meant to fit into inkjet printers instead of cartridges made specifically for the printer by companies such as Epson, HP, Lexmark, Canon and others. These cartridges made by third parties can be significantly cheaper than those made by the printer manufacturers. They may also be refillable.