A Member of Parliament (MP) is the representative of the voters to a parliament. In many countries with bicameral parliaments, this category includes specifically members of the lower house, as upper houses often have a different title.
Members of parliament tend to form parliamentary groups (also called parliamentary parties) with members of the same political party.
Great Britain elects members of three parliaments:
The Parliament of the Great Britain, with 650 members elected by the first-past-the-post system to the (lower) House of Commons, referred to as Members of Parliament, abbreviated to MP