In English common law, fee tail or entail is a form of trust established by deed or settlement which restricts the sale or inheritance of an estate in real property and prevents the property from being sold, devised by will, or otherwise alienated by the tenant-in-possession, and instead causes it to pass automatically by operation of law to an heir pre-determined by the settlement deed. The term fee tail is from Medieval Latin feodum talliatum, which means "cut(-short) fee", and is in contrast to "fee simple" where no such restriction exists and where the possessor has an absolute title (although subject to the allodial title of the monarch) in the property which he can bequeath or otherwise dispose of as he wishes. Equivalent legal concepts exist or formerly existed in many other European countries and elsewhere.
The fee tail allowed a patriarch to perpetuate his blood-line, family-name, honour and armorials in the persons of a series of powerful and wealthy male descendants. By keeping his estate intact in the hands of one heir alone, in an ideally indefinite and pre-ordained chain of succession, his own wealth, power and family honour would not be dissipated amongst several male lines, as became the case for example in Napoleonic France by operation of the Napoleonic Code which gave each child the legal right to inherit an equal share of the patrimony, where a formerly great landowning family could be reduced in a few generations to a series of small-holders or peasant farmers. It therefore approaches the true corporation which is a legal body or person which does not die and continues in existence and can hold wealth indefinitely. Indeed, as a form of trust, whilst the individual trustees may die, replacements are appointed and the trust itself continues, ideally indefinitely. In England almost seamless successions were made from patriarch to patriarch, the smoothness of which were often enhanced by baptising the eldest son and heir with his father's Christian name for several generations, for example the FitzWarin family, all named Fulk. Such indefinite inalienable land-holdings were soon seen as restrictive on the optimum productive ability of land, which was often converted to deer-parks or pleasure grounds by the wealthy tenant-in-possession, which was damaging to the nation as a whole, and thus laws against perpetuities were enacted, which restricted entails to a maximum number of lives.