mortmain Meaning, Definition & Usage

  1. noun real property held inalienably (as by an ecclesiastical corporation)
    dead hand.
  2. noun the oppressive influence of past events or decisions
    dead hand of the past; dead hand.

WordNet

Mort"main` noun
Etymology
F. mort, morte, dead + main hand; F. main-morte. See Mortal, and Manual.
Definitions
  1. (Law) Possession of lands or tenements in, or conveyance to, dead hands, or hands that cannot alienate. ✍ The term was originally applied to conveyance of land made to ecclesiastical bodies; afterward to conveyance made to any corporate body. Burrill.

Webster 1913