erythromycin, Erythrocin, E-Mycin, Ethril, Ilosone, Pediamycin - an antibiotic (trade name Erythrocin or E-Mycin or Ethril or Ilosone or Pediamycin) obtained from the actinomycete Streptomyces erythreus; effective against many Gram-positive bacteria and some Gram-negative --1is a kind ofantibiotic, antibiotic drug