1. One who receives or entertains guests in a social or official capacity.
2. A person who manages an inn or hotel.
3. One that furnishes facilities and resources for a function or event: the city chosen as host for the Olympic Games.
4. The emcee or interviewer on a radio or television program.
5. Biology The animal or plant on which or in which another organism lives.
6. Medicine The recipient of a transplanted tissue or organ.
7. Computer Science A computer containing data or programs that another computer can access by means of a network or modem.

Usage Note: Host was used as a verb in Shakespeare's time, but this usage was long obsolete when the verb was reintroduced (or perhaps reinvented) in recent years to mean "perform the role of a host." The usage occurs particularly in contexts relating to institutional gatherings or television and radio shows, where the person performing the role of host has not personally invited the guests. Perhaps because the verb involves a suspect extension of the traditional conception of hospitality, it initially met with critical resistance. In a 1968 survey only 18 percent of the Usage Panel accepted the usage in the sentence The Cleveland chapter will host this year's convention. Over time, however, the usage has become increasingly well established and has the useful purpose of describing the activities of one who performs the ceremonial or practical role of a host, as in arranging a conference or welcoming guests. In our 1986 survey, 53 percent of the Panelists accepted the usage in the phrase a reception hosted by the Secretary of State. The verb is less well accepted when it is used to describe the role of a performer who acts as a master of ceremonies for a broadcast or film, where the relation of the word to the notion of "hospitality" is stretched still further.

1. An army.
2. A great number; a multitude. See Synonyms at multitude.

1. 1. The larger of two organisms in a symbiotic relationship.
   2. An organism or cell on or in which a parasite lives or feeds. ◇ A definitive host is an organism in which a parasite reaches sexual maturity. The anopheles mosquito is the definitive host for the malaria plasmodium because, while the mosquito is not adversely affected by the plasmodium's presence, it is the organism in which the plasmodium matures and reproduces. ◇ An intermediate host is an organism in which a parasite develops but does not attain sexual maturity. Humans and certain other vertebrates are the intermediate host of the malaria plasmodium. ◇ A paratenic host is an organism which may be required for the completion of a parasite's life cycle but in which no development of the parasite occurs. The unhatched eggs of nematodes are sometimes carried in a paratenic host such as a bird or rodent. When a predator eats the paratenic host, the eggs are ingested as well.
2. The recipient of a transplanted tissue or organ.
3. A computer containing data or programs that another computer can access by means of a network or modem.