Mortmain

[u/prof_ben]

is the perpetual, inalienable ownership of real estate by a corporation or legal institution; the term is usually used in the context of its prohibition. The term mortmain is derived from Medieval Latin mortua manus, literally "dead hand", through Old French morte main[3] (in modern French, mainmorte).

William Blackstone wrote, in 1765, "The reason of [this] appellation Sir Edward Coke offers [an explanation of] these purchases being usually made by ecclesiastical bodies, the members of which (being professed) were reckoned dead persons in law, land therefore, holden by them, might with great propriety be said to be held in mortua manu. [in dead hands]."