1. a person who receives or entertains guests, esp in his own home 2. a. a country or organization which provides facilities for and receives visitors to an event b. (as modifier): the host nation. 3. (Broadcasting) the compere of a show or television programme 4. (Biology) biology a. an animal or plant that nourishes and supports a parasite b. an animal, esp an embryo, into which tissue is experimentally grafted 5. (Computer Science) computing a computer connected to a network and providing facilities to other computers and their users 6. (Commerce) the owner or manager of an inn.