ENGLISH
REFERENCE

antibiotic

n. · adj.
US //ˌæntaɪbaɪˈɑtɪk// UK //ˌæntɪbaɪˈɒtɪk// an·tibi·ot·ic
  1. 1 medicine for infections (n.)
    B2 Upper Intermediate Medicine

    a medicine that doctors give you to kill bacteria and cure an infection.

    a pharmacological agent used to treat bacterial infections by inhibiting growth or destroying the pathogen.

    Example

    The doctor prescribed a ten-day course of antibiotics to clear up my ear infection.

    Example

    The physician emphasized the importance of completing the entire course of antibiotics to prevent the development of drug-resistant bacterial strains.

    Usage

    often used in the plural when referring to a course of treatment.

    Teacher's tip

    Learners often confuse antibiotics with antivirals; remind them that antibiotics only work against bacteria, not viruses like the common cold.
  2. 2 relating to antibiotics (adj.)
    B2 Upper Intermediate Science

    describing something that relates to or works like an antibiotic.

    pertaining to the properties or use of antibiotics.

    Example

    Some plants have natural antibiotic properties that help them fight off diseases.

    Example

    The research team is investigating the antibiotic effects of various soil-dwelling fungi in the hope of discovering new treatments.

    Usage

    usually placed before the noun.
Origin

Borrowed from French antibiotique; by surface analysis, anti- + -biotic.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

Last updated June 20, 2026