parasitism

noun

1. Biology. a relation between organisms in which one lives as a parasite on another.
2. a parasitic mode of life or existence.
3. Pathology. a diseased condition due to parasites.
4. (in some totalitarian countries)
   1. unemployment or refusal to work.
   2. employment in work considered nonessential by the state.

noun

1. the relationship between a parasite and its host
2. the state of being infested with parasites
3. the state of being a parasite

n.1610s, from parasite + -ism. Biological sense is from 1853. n.

1. A symbiotic relationship in which one species, the parasite, benefits at the expense of the other, the host.

1. A relationship between two organisms in which one organism (the parasite) benefits and the other (the host) is harmed. Parasites derive nutrition from their host and may also gain other benefits such as shelter and a habitat in which to grow and reproduce. See more at parasite. Compare amensalism commensalism mutualism.