any spherical Gram-positive bacterium of the genus Staphylococcus, typically occurring in clusters and including many pathogenic species, causing boils, infection in wounds, and septicaemia: family MicrococcaceaeOften shortened to: staph
(plural staphylococci), 1887, Modern Latin, the genus name, coined (on model of streptococcus) in 1882 by Scottish surgeon and bacteriologist Alexander Ogston (1844-1929), from Greek staphyle "bunch of grapes" (see staff (n.)) + Modern Latin coccus "spherical bacterium," from Greek kokkos "berry, grain" (see cocco-). So called because the bacteria usually bunch together in irregular masses.
Any of various bacteria of the genus Staphylococcus that are gram-positive cocci and are normally found on the skin and mucous membranes of warm-blooded animals. Pathogenic strains such as S. aureus commonly cause infections of the skin, bones, lungs and other organs. Some staphylococcal disease, such as food poisoning, is caused by a toxin produced by the bacteria.