A parliament is a legislative body, especially in those countries whose system of government is derived from that of the United Kingdom.
In the United Kingdom, Parliament consists of the House of Commons, the House of Lords, and the Monarch, although the role of the Queen as part of the Parliament is generally omitted by non-legal commentators. The House of Lords is unique among those Parliaments that have adopted the Westminster system, in that it combines judicial and legislative functions. However, separation of its judicial functions into a separate body has been planned ever since the original Judicature Act 1873, and in the long run is probably inevitable.
In a similar fashion, the Australian Parliament consists of the House of Representatives, the Senate and the Queen, although the Australian Senate is modelled after the United States Senate, not the House of Lords.
Closer in that regard to the British model is the Parliament of Canada, which consists of the House of Commons, the Senate and the Queen. The Canadian Senate, like the House of Lords, is an appointed, not elected, body. But the Canadian Senate contains only the equivalent of Life Peers, lacking any members who hold their seat by inheritance or through a religious office such as bishop.
Parliaments originated as meetings hosted by the sovereign of the leading nobles and commoners of the kingdom; this explains the Queen's role as part of the British, Australian and Canadian institutions.
The British Parliament is traditionally referred to as the Mother of Parliaments, due to the way this institution has been the model for other parliamentary systems.