From WordNet (r) 3.0 (2006):
host
n 1: a person who invites guests to a social event (such as a
party in his or her own home) and who is responsible for
them while they are there
2: a vast multitude [syn: horde, host, legion]
3: an animal or plant that nourishes and supports a parasite; it
does not benefit and is often harmed by the association [ant:
parasite]
4: a person who acts as host at formal occasions (makes an
introductory speech and introduces other speakers) [syn:
master of ceremonies, emcee, host]
5: archaic terms for army [syn: host, legion]
6: any organization that provides resources and facilities for a
function or event; "Atlanta was chosen to be host for the
Olympic Games"
7: (medicine) recipient of transplanted tissue or organ from a
donor
8: the owner or manager of an inn [syn: host, innkeeper,
boniface]
9: a technical name for the bread used in the service of Mass or
Holy Communion
10: (computer science) a computer that provides client stations
with access to files and printers as shared resources to a
computer network [syn: server, host]
v 1: be the host of or for; "We hosted 4 couples last night"