Peerage of England
The ranks of the English peerage are, in descending order, Duke, Marquess, Earl, Viscount, and Baron. While most newer English peerages descend only in the male line, many of the older ones (particularly older baronies) can descend through females. Under English inheritance law all daughters are co-heirs, so many older English peerage titles have fallen into abeyance between various female co-heirs.
Peerages in the United Kingdom
Baronets, while holders of hereditary titles, are not peers since baronetcies have never conferred noble status, although socially they came to be regarded as part of the aristocracy. Knights, Dames and holders of other British non-hereditary chivalric orders, decorations, and medals are likewise not peers.