Important definitions you should know when buying ink online:

Genuine or OEM (Original Equipment Manufacturer) - Ink cartridges labeled genuine or OEM are made by the same company that made your printer and they are the same as the original that was supplied with your printer when it was new. Basically, these are name-brand replacements and are typically the most expensive.

Compatible or Aftermarket - Specifically designed replacements that meet the same specifications as the OEM cartridge but are not manufactured by the name-brand company. These are typically inexpensive but since there are many manufacturers, quality may vary. Finding a reliable manufacturer is important but you can save a great deal of money.

Refurbished - Typically, these are OEM cartridges that have been overhauled, refilled, and tested. They have had worn or damaged parts replaced and have been refilled with OEM ink. These will be less expensive than new OEM cartridges but more expensive than compatible cartridges.

Remanufactured - Depending on the website, this can refer to compatible or refurbished ink cartridges.