Merriam-Webster Collegiate Dictionary - mortmain

 noun  Etymology: Middle English morte-mayne, from Anglo-French ~, from morte (feminine of mort dead) + main hand, from Latin manus — more at manual  Date: 15th century  1.  a. an inalienable possession of lands or buildings by an ecclesiastical or other corporation  b. the condition of property or other gifts left to a corporation in perpetuity especially for religious, charitable, or public purposes  2. the influence of the past regarded as controlling the present