Anfitrião vs. hospedeiro
While both words can translate to "host" in English, usage depends heavily on the context and the region. generally, anfitrião describes a person receiving guests socially (parties, dinners), while hospedeiro is technical, often referring to biology or, specifically in Portugal, to flight attendants.
Anfitrião
B1This is the standard word in both Brazil and Portugal for a social host. It refers to the person who invites guests to their home, organizes a party, or presents a television show.
O anfitrião recebeu os convidados com um grande sorriso.
(The host welcomed the guests with a big smile.)
Ela sempre foi uma excelente anfitriã nos jantares de família.
(She has always been an excellent host at family dinners.)
O Brasil foi o anfitrião da Copa do Mundo de 2014.
(Brazil was the host of the 2014 World Cup.)
Temos que agradecer ao anfitrião pela hospitalidade.
(We have to thank the host for the hospitality.)
Hospedeiro
C1In Brazil, this word is almost exclusively used in biology to describe an organism that harbors a parasite. In Portugal, it is also used in biology, but it is frequently the title for a flight attendant (hospedeiro de bordo) or ground staff at events; it is rarely used for a social host.
O hospedeiro de bordo pediu aos passageiros que apertassem os cintos.
(The flight attendant asked the passengers to fasten their seatbelts (European Portuguese usage).)
Certos insetos funcionam como hospedeiro para vírus perigosos.
(Certain insects function as a host for dangerous viruses (Biological usage).)
A companhia aérea está a contratar novos hospedeiros.
(The airline is hiring new flight attendants (European Portuguese usage).)
O hospedeiro intermediário transmite a doença para os humanos.
(The intermediate host transmits the disease to humans (Biological usage).)
Summary
Use anfitrião when referring to a person organizing a social event, dinner, or party in both Brazil and Portugal. Avoid using hospedeiro for social situations; in Brazil, it usually refers to the biological host of a parasite, and in Portugal, it often refers to a flight attendant or event staff.