Parasts

Parasts is a term that appears in scattered scholarly and literary contexts to describe interactions or entities that lie between parasitism and other forms of association. It does not have a universally accepted definition, and its meaning varies by field and author.

In biology and ecology, some writers use parasts to refer to borderline interactions in which an organism derives resources from a host with harm that is limited, variable, or reversible, or in which the relationship can shift toward mutualism or commensalism under certain conditions. The term is not widely adopted, and traditional categories such as parasitism, mutualism, and commensalism remain the standard framework for describing host–organism relationships.

In speculative fiction and philosophy, parasts may describe agents, processes, or entities that borrow energy, information, or metabolic products from a host or system without establishing a fixed parasitic model. In these contexts, the concept often emphasizes ambiguity, control, and ethical implications of interaction.

Etymology and history of parasts are unsettled due to its irregular use and lack of formal adoption. The term emerged in late 20th to 21st-century discourse and has not achieved consensus or widespread standardization.

See also: parasitism, mutualism, commensalism, symbiosis, host–parasite dynamics.