English Reference
noun

infection

n.
US /ˌɪnˈfɛkʃən/ UK /ɪnfˈɛkʃən/ in·fec·tion UK spelling infection's, infection's

  1. 01 B1 Intermediate Medicine

    the act of germs or bacteria entering a person's body and starting to grow.

    the process by which a pathogen invades a host organism and begins to multiply.

    Simple

    The doctor cleaned the wound carefully to prevent an infection from starting.

    In context

    Public health officials focused on the primary infection route, which appeared to be contaminated water sources in the rural districts.

  2. 02 B1 Intermediate Medicine

    a disease or sickness caused by bacteria, viruses, or other germs.

    a disease state resulting from the presence and activity of a pathogenic agent.

    Simple

    She had a throat infection and had to stay home from work for three days.

    In context

    The patient was diagnosed with a secondary bacterial infection following a severe bout of seasonal influenza.

  3. 03 B2 Upper Intermediate Medicine

    a visible sign of a disease, such as redness or swelling around a cut.

    the physical manifestation or site of a pathogenic presence, often characterized by inflammation or suppuration.

    Simple

    The nurse noticed a small infection around the stitches on his arm.

    In context

    The surgeon examined the site for signs of localized infection, noting the absence of redness or discharge during the follow-up appointment.

Usage infection prevention · infections more often

When they die, their bodies may be taken back to their villages, thus multiplying contacts and the risk of further infections.

UN News· 10 Aug 2026

That can spread nasty infections like cold sores.

BBC News· 30 Jul 2026

From Old French infection, from Late Latin īnfectiō. Equivalent to infect + -ion.

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

This entry
Origin la-lat īnfectiō
Level B2 · Upper Intermediate
Frequency Common
Updated