Peers are members of the House of Lords.
Lords fall into one of three groups - the Lords Temporal, the Lords Spiritual and the Lords of Appeal (Law Lords).
Peers are technically unelected members of Parliament (MP) but this term is used exclusively to describe the elected members of the House of Commons.
As a result of reforms to the House of Lords, all peers now sit in the House by virtue of a life peerage.
This includes the 92 hereditary peers who were allowed to retain their membership when the House of Lords Act 1999 withdrew the right of the other 650 hereditary peers to sit in the upper chamber.
The Lords Spiritual sit by virtue of their position in the Church of England and not as peers in their own right.
Law Lords are usually senior judges who have been given life peerages so that they can carry out the judicial work of the House of Lords.
But as of October 2009, the Law Lords will lose their right to sit in the House of Lords when a supreme court will be established which will be independent of Parliament.