A passport is a document, issued by a national government

Government

Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...

, which certifies, for the purpose of international travel, the identity and nationality of its holder. The elements of identity are name, date of birth, sex, and place of birth.

A passport does not of itself entitle the passport holder entry into another country, nor to consular protection

Consular assistance

Consular assistance is help and advice provided by the diplomatic agents of a country to citizens of that country who are living or traveling overseas.Such assistance may take the form of:* provision of replacement travel documents...

 while abroad or any other privileges. It does, however, normally entitle the passport holder to return to the country that issued the passport.