any of a major group of broad-spectrum antibiotics produced by, or derived from, a fungus (genus Cephalosporium): an alternative for people allergic to penicillin
See cephalosporin in American Heritage Dictionary 4
(sĕf-ə-lə-spôrˈĭn, -spōrˈ-)
noun
Any of various broad-spectrum antibiotics, closely related to the penicillins, that were originally derived from the fungus Cephalosporium acremonium.