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parasite

PAIR-uh-syyt /ˈpær.ə.saɪt/

nounB2IELTSTOEFLGRESAT

academicgeneral

An organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense.

Implies a one-sided biological relationship where the host is harmed while the parasite gains food or shelter.

The story behind the word. From Greek 'parasitos', literally meaning 'one who eats beside another' (para = beside + sitos = food). In ancient Greece, the term originally described minor officials who attended public banquets to eat at public expense, before biologists repurposed it for free-loading organisms.

Word relationships

bloodsucker: Bloodsucker is an informal, often derogatory term; parasite is the formal scientific term for any organism exploiting a host.

host: The host provides nourishment or shelter to the parasite, usually suffering harm in the process.

Commonly confused with

symbiont: A symbiont can live in a mutually beneficial partnership, whereas a parasite strictly harms its host.

Word family

parasitic (adjective): Relating to or characteristic of a parasite.
parasitism (noun): The practice of living as a parasite.

Collocations

host and parasite
intestinal parasite
external parasite
parasite infection

Example sentences

"The tick acts as an external parasite, clinging to mammalian hosts to feed on their blood." Parasitology
"A deadly intestinal parasite weakened the wild population, making individuals easy targets for local predators." Ecology

Memory hook

A PARASITE sits PARAllel to your food and eats SITE (sight) unseen. Para (beside) + sitos (food) = eating beside another's dish.

When not to use

Do not confuse with mutualistic symbionts that help their host partner.

Fun facts

Some parasitic fungi can take control of an ant's brain, forcing it to climb a plant stem and clamp onto a leaf before the fungus blooms!