An antibiotic is a substance used to kill bacteria. If you're coughing up green stuff, the doctor might give you an antibiotic to fight the infection.

Since the prefix anti- means fighting, opposing, or killing, and bios is the Greek word for "life," antibiotic literally means life-killing. But doctors prescribe them primarily to kill the bacteria responsible for infections in the body. (A virus, on the other hand, cannot be treated with an antibiotic, so doctors are always making a distinction between a virus and a bacterial infection.) You can also use antibiotic as an adjective. Some plants have natural antibiotic effects when eaten.

Definitions of antibiotic
  1. noun
    a chemical substance derivable from a mold or bacterium that can kill microorganisms and cure bacterial infections
    “when antibiotics were first discovered they were called wonder drugs”
    synonyms: antibiotic drug
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    any of various red antibiotics isolated from soil bacteria
    an antibiotic and antifungal agent
    a crystalline antibiotic active against various fungi
    antineoplastic antibiotic
    an antibiotic drug used as an antineoplastic in chemotherapy
    Azactam, aztreonam
    an antibiotic (trade name Azactam) used against severe infections; has minimal side effects
    a polypeptide antibiotic of known chemical structure effective against several types of Gram-positive organisms; usually applied locally
    a colorless basic antibiotic that inhibits the growth of Gram-positive organisms
    Kafocin, cephaloglycin
    antibiotic related to cephalosporin but no longer in common use
    a broad spectrum semisynthetic antibiotic produced by modifying cephalosporin
    Mefoxin, cephalosporin
    one of several broad spectrum antibiotic substances obtained from fungi and related to penicillin (trade names Mefoxin); addition of side chains has produced semisynthetic antibiotics with greater antibacterial activity
    Chloromycetin, chloramphenicol
    an oral antibiotic (trade name Chloromycetin) used to treat serious infections (especially typhoid fever)
    Aureomycin, chlortetracycline
    a yellow crystalline antibiotic (trade name Aureomycin) used to treat certain bacterial and rickettsial diseases
    Cipro, ciprofloxacin
    an oral antibiotic (trade name Cipro) used against serious bacterial infections of the skin or respiratory tract or urinary tract or bones or joints
    an antibiotic that is especially active against the tubercle bacillus
    antibiotic consisting of a hydrogenated form of streptomycin; used against tuberculosis and tularemia and Gram-negative organisms
    an antibiotic used as an anticancer drug
    Vibramycin, doxycycline
    an antibiotic derived from tetracycline that is effective against many infections
    E-Mycin, Erythrocin, Ethril, Ilosone, Pediamycin, erythromycin
    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
    Garamycin, gentamicin
    an antibiotic (trade name Garamycin) that is derived from an actinomycete; used in treating infections of the urinary tract
    an antibiotic produced by a soil bacterium; used chiefly as an antiseptic in treating local infections produced by Gram-positive bacteria
    Kantrex, kanamycin
    antibiotic (trade name Kantrex) used to treat severe infections
    Lincocin, lincomycin
    antibiotic (trade name Lincocin) obtained from a streptomyces bacterium and used in the treatment of certain penicillin-resistant infections
    Mutamycin, mitomycin
    a complex of antibiotic substances obtained from a streptomyces bacterium; one form (trade name Mutamycin) shows promise as an anticancer drug
    a highly unsaturated antibiotic acid obtained from an actinomycete
    Neobiotic, fradicin, neomycin
    an antibiotic obtained from an actinomycete and used (as a sulphate under the trade name Neobiotic) as an intestinal antiseptic in surgery
    an antibiotic obtained from an actinomycete and used to treat infections by Gram-positive bacteria
    Mycostatin, Nystan, nystatin
    an antifungal and antibiotic (trade names Mycostatin and Nystan) discovered in New York State; derived from soil fungi actinomycetes
    Terramycin, hydroxytetracycline, oxytetracycline, oxytetracycline hydrochloride
    a yellow crystalline antibiotic (trademark Terramycin) obtained from a soil actinomycete; used to treat various bacterial and rickettsial infections
    any of various antibiotics obtained from Penicillium molds (or produced synthetically) and used in the treatment of various infections and diseases
    any of several toxic antibiotics obtained from a particular soil bacterium
    trade name for a parenteral antibiotic
    a yellow-green mixture of antibiotics obtained from the bacillus of green pus
    a toxic blue crystalline antibiotic found in green pus
    an antibiotic used to treat gonorrhea
    an antibiotic produced by the actinomycete Streptomyces griseus and used to treat tuberculosis
    a basic antibiotic derived from a soil actinomycete
    a polypeptide antibiotic (similar to bacitracin) obtained from a soil bacterium
    Nebcin, tobramycin
    an antibiotic (trade name Nebcin) that is especially effective against Gram-negative bacteria
    tyrocidin, tyrocidine
    a basic polypeptide antibiotic derived from a soil bacterium; a major component of tyrothricin
    a mixture of antibiotics applied locally to infections caused by Gram-positive bacteria
    Vancocin, vancomycin
    an antibiotic (trade name Vancocin) effective against some bacterial infections
    Viocin, viomycin
    a basic polypeptide antibiotic (trade name Viocin) administered intramuscularly (along with other drugs) in the treatment of tuberculosis
    Amoxil, Augmentin, Larotid, Polymox, Trimox, amoxicillin
    an antibiotic; a semisynthetic oral penicillin (trade names Amoxil and Larotid and Polymox and Trimox and Augmentin) used to treat bacterial infections
    Polycillin, Principen, SK-Ampicillin, ampicillin
    semisynthetic penicillin (trade names Principen and Polycillin and SK-Ampicillin)
    Ultracef, cefadroxil
    a cephalosporin antibiotic (trade name Ultracef)
    Cefobid, cefoperazone
    a parenteral cephalosporin (trade name Cefobid) used for severe infections
    Claforan, cefotaxime
    a parenteral cephalosporin (trade name Claforan) used for severe infections of the lungs or throat or ears or urinary tract
    Fortaz, Tazicef, ceftazidime
    a parenteral cephalosporin (trade names Fortaz and Tazicef) used to treat moderate infections
    Rocephin, ceftriaxone
    a parenteral cephalosporin (trade name Rocephin) used for severe infection of the lungs or throat or ears or urinary tract
    Ceftin, Zinacef, cefuroxime
    a cephalosporin that can be given parenterally (trade name Zinacef) or orally by tablets (trade name Ceftin); indicated for infections of the lungs or throat or ears or urinary tract or meninges
    Keflex, Keflin, Keftab, cephalexin
    an oral cephalosporin (trade names Keflex and Keflin and Keftab) commonly prescribe for mild to moderately severe infections of the skin or ears or throat or lungs or urinary tract
    a semisynthetic analogue of cephalosporin
    Fulvicin, griseofulvin
    a kind of penicillin (a fungicidal antibiotic with the trade name Fulvicin) produced by molds of the genus Penicillium
    antibiotic drug of the penicillin family used in the treatment of certain staphylococcal infections
    Mithracin, mithramycin
    an antineoplastic drug (trade name Mithracin) used to treat cancer of the testes
    penicillinase-resistant antibiotic
    a form of penicillin that is not rendered inactive by penicillinase
    penicillin F
    the first form of penicillin that was isolated in Great Britain
    benzylpenicillin, penicillin G
    the penicillin that constitutes the principal component of many commercial antibiotics
    penicillin O
    a penicillin that is similar in antibiotic action to penicillin G but is obtained differently
    penicillin V, phenoxymethyl penicillin
    a crystalline penicillin similar in action to penicillin G but more resistant to the action of gastric acids
    Pipracil, piperacillin
    a synthetic type of penicillin antibiotic (trade name Pipracil) used for moderate to severe infections
    type of:
    antibacterial, antibacterial drug, bactericide
    any drug that destroys bacteria or inhibits their growth
  2. adjective
    of or relating to antibiotic drugs
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