parasitism

noun

par·​a·​sit·​ism ˈper-ə-sə-ˌti-zəm 

-ˌsī-,

ˈpa-rə-

1

: the behavior of a parasite

2

: an intimate association between organisms of two or more kinds

especially : one in which a parasite obtains benefits from a host which it usually injures

3

: parasitosis

Examples of parasitism in a Sentence

Recent Examples on the Web

But the species, beset by a combination of overfishing and parasitism by invasive, non-native sea lampreys, began to decline precipitously in number, according to the Minnesota Department of Natural Resources. —Steven Martinez, Journal Sentinel, 25 Nov. 2024

The second- and third-most impactful factors were wolf predation and parasitism by carotid arterial worms (E. schneideri). —Katie Hill, Outdoor Life, 6 Nov. 2024

Our understanding of them has barely scratched the surface—there’s more to learn about the specifics of its reproductive cycle, for instance—and their existence will continue to challenge our understanding of symbiosis, parasitism and the delicate interplay between different species. —Scott Travers, Forbes, 17 Aug. 2024

That parasitism has cropped up so many times in unrelated species — and thus evolved again and again — speaks to its success as an adaptive strategy. —Kate Golembiewski, Discover Magazine, 1 Aug. 2024

Word History

First Known Use

circa 1611, in the meaning defined at sense 1

Kids Definition

parasitism

noun

par·​a·​sit·​ism ˈpar-ə-sə-ˌtiz-əm 

-ˌsīt-ˌiz-

: a close association between living things of two or more kinds of which one is a parasite obtaining benefits from the other which is a host and is usually harmed in some way

Medical Definition

parasitism

noun

par·​a·​sit·​ism ˈpar-ə-sə-ˌtiz-əm  -ˌsīt-ˌiz- 

1

: an intimate association between organisms of two or more kinds

especially : one in which a parasite obtains benefits from a host which it usually injures

2

: parasitosis