What does antibiotic mean?
An antibiotic is a substance that kills bacteria or prevents them from multiplying, making it one of the most important classes of medicine in modern history. Used to treat bacterial infections ranging from strep throat to pneumonia, antibiotics transformed once-fatal illnesses into manageable conditions after the discovery of penicillin in the early twentieth century. The word also serves as an adjective describing anything with bacteria-killing properties, as in 'antibiotic treatment'. In everyday speech, 'antibiotics' most often refers to prescription medicines, commonly discussed in phrases like 'a course of antibiotics'. The term carries significant contemporary weight because of antibiotic resistance — the growing ability of bacteria to survive these drugs through overuse and misuse. Understanding the word includes knowing its limits: antibiotics are ineffective against viruses such as those causing colds and influenza, a distinction central to public health messaging worldwide.
A substance, such as penicillin or tetracycline, that destroys or inhibits the growth of bacteria and is used to treat bacterial infections.
"The physician prescribed a broad-spectrum antibiotic to treat the pneumonia."
Usually used in the plural ('antibiotics') when referring to medication generally; singular use often names a specific drug class or instance.
Relating to, involving, or having the property of destroying or inhibiting the growth of bacteria.
"The researchers tested the sample's antibiotic properties against several bacterial strains."
The plural is the standard form in medical and everyday contexts, since antibiotics are usually discussed as a class of drugs rather than individually.
"He was given antibiotics intravenously during his hospital stay."
Alexander Fleming discovered the first antibiotic, penicillin, by accident in 1928 when mould contaminated his petri dish — a mistake that has since saved hundreds of millions of lives.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of antibiotic
The word 'antibiotic' combines the Greek-derived prefix 'anti-', meaning 'against', with 'biosis', from Greek 'bios', meaning 'life' — literally 'against life', referring to its action against living microorganisms. It entered English usage in the mid-twentieth century, coinciding with the golden age of antibiotic discovery following Alexander Fleming's identification of penicillin in 1928. The term shares its Greek roots with related scientific words such as 'antiseptic', 'antibody', and 'symbiotic', all drawing on the same classical vocabulary of life and opposition.
How antibiotic is actually used
Strictly speaking, antibiotics act against bacteria, not viruses — doctors often stress this because patients frequently expect them for colds and flu. The word functions both as a countable noun (an antibiotic, antibiotics) and, less commonly, as an adjective describing substances with antibacterial properties.
Easily confused with antibiotic
An antibody is a protein produced by the immune system to neutralize pathogens, whereas an antibiotic is a drug used to kill or inhibit bacteria.
An antiseptic is applied externally to living tissue to prevent infection, while an antibiotic is typically taken internally to treat bacterial infections.