Staph is the common name for a group of bacteria in the genus Staphylococcus. This latter word may sound intimidating, but by breaking it down, we find that “staph” is Latin for grape-like clusters, and “coccus” is Latin for round, meaning that this is a group of bacteria that appear under the microscope as round, grape-like clusters. On the Staph Fast Facts homepage, there are two pictures of staph that illustrate how scientists came up with this bacteria's name due to its appearance. There are over 30 species of staph, with the most common in humans being Staphylococcus aureus and Staphylococcus epidermidis.