Definition - What does Host Organism mean?
A host organism is an organism that harbours a parasite and supplies it with nutrients. A host is not merely the term to describe the supplier of nutrients in a parasitic relationship, however, but can also be applied to nutrient suppliers in mutually beneficial, symbiotic relationships. Plants which supply nutrients to epiphytes are called hosts, but the term is applied loosely in this regard.
Safeopedia explains Host Organism
Examples of host organisms include, but are not limited to, a cell supplying nutrients to a malicious virus, animals being hosts to intestinal worms, bean plants being hosts to nitrogen-forming bacteria which are helpful, etc.. There are also different names for different kinds of host organisms based on how they behave with a virus. A definitive host, for example, is a host cell where a virus reaches maturity and reproduces sexually.