1) Antibiotic 2) Antibiotic drug 
A group of peptide antibiotic agents, isolated from several species of Streptomyces (originally Actinomyces), that are active against Gram-positive bacteria, fungi, and neoplasms. Actinomycins are chromopeptides, most containing the chromophore actinocin, and are derivatives of phenoxazine that differ in their amino acids and their sequence in the ...
(ak″tĭ-no-mi´sin) a family of antibiotics from various species of Streptomyces, which are active against bacteria and fungi; it includes the antineoplastic agentdactinomycin (actinomycin D).
[n] - any of various red antibiotics isolated from soil bacteria
noun any of various red antibiotics isolated from soil bacteria
any of a group of related antibiotics derived from several species of streptomyces bacteria, used against susceptible bacteria and fungi and in the treatment of various cancers.