English Reference
noun

virus

n.
US /ˈvaɪɹəs/ UK /vˈaɪɹəs/ virus UK spelling virus's, viruses

  1. 01 A2 Elementary Science

    a tiny living thing that enters your body and can make you sick.

    a submicroscopic infectious agent that replicates only inside the living cells of an organism.

    Simple

    The doctor said my sore throat was caused by a common virus.

    In context

    Researchers are studying how the virus mutates when it moves from animal hosts to human populations.

  2. 02 B1 Intermediate Informal Medicine

    a sickness or infection caused by a virus.

    an illness or medical condition resulting from a viral infection.

    Simple

    I missed three days of work because of a stomach virus.

    In context

    The school reported a high number of absences this week due to a seasonal respiratory virus circulating among the students.

  3. 03 B1 Intermediate Computing

    a harmful computer program that can copy itself and damage your files.

    a piece of code which is capable of copying itself and typically has a detrimental effect, such as corrupting the system or destroying data.

    Simple

    Never click on suspicious links or you might get a virus on your laptop.

    In context

    The company's security software detected a sophisticated virus that was attempting to encrypt sensitive financial records.

  4. 04 C1 Advanced Literary

    something bad or dangerous that spreads quickly from person to person.

    a harmful or corrupting influence that spreads rapidly within a group or society.

    Simple

    Hatred can spread like a virus through a community.

    In context

    The orator warned that misinformation was a virus threatening the very foundations of their democratic institutions.

Usage virus disease · virus outrun


From Middle English virus, from Latin vīrus (“poison, slime, venom”), via rhotacism from Proto-Italic weizos, from Proto-Indo-European wisós (“fluidity, slime, poison”). First use in the computer context by David Gerrold in his 1972 book When HARLIE Was One.

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

This entry
Origin ine-pro *wisós
Level A2 · Elementary
Frequency Common
Updated