English Reference
noun

parasite

n.
US /ˈpɛɹəˌsaɪt/ UK /pˈæɹəsˌaɪt/ par·a·site UK spelling parasite's, parasite's

  1. 01 B2 Upper Intermediate Biology

    a plant or animal that lives on or inside another living thing and gets its food from it.

    an organism that lives in or on an organism of another species (the host) and derives nutrients at the host's expense.

    Simple

    The doctor explained that the stomach pain was caused by a parasite from the dirty water.

    In context

    The life cycle of this particular parasite requires two different hosts to reach maturity before it can reproduce effectively.

    hostsymbiote
  2. 02 C1 Advanced Informal

    a person who takes money, food, or help from others but never does anything to help in return.

    a person who habitually relies on or exploits others and gives nothing in return. Often used as a derogatory social or political label.

    Simple

    He hasn't had a job in years and just lives like a parasite off his parents.

    In context

    The editorial attacked the corrupt officials, describing them as parasites who drained the country's resources while the public suffered.

    leechfreeloaderhanger on
  3. 03 C2 Proficiency Technical Aviation

    a smaller plane that is carried and launched by a much larger aircraft.

    a component of a composite aircraft that is carried aloft and air-launched by a larger carrier aircraft or mother ship.

    Simple

    The experimental rocket was launched as a parasite from the wing of a heavy bomber.

    In context

    Engineers evaluated the aerodynamic interference between the mother ship and the parasite aircraft during the high-altitude release sequence.

    parasite aircraft
    mother shipcarrier

Aquatic parasites can also kill important food sources such as fish and crab and can harm tourism and recreational activities.

Phys.org· 16 Aug 2026

Can a high-transmission host be identified simply by measuring the number of parasites it sheds?

Phys.org· 14 Aug 2026

From Middle French parasite, from Latin parasitus, from Ancient Greek παράσιτος (parásitos, “person who eats at the table of another”), from noun use of adjective meaning "feeding beside", from παρά (pará, “beside”) + σῖτος (sîtos, “food”).

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

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated