perpetuity

noun

1. 1

   The quality or state of being perpetual; endless duration; uninterrupted existence.

2. 2

   Something that is perpetual.

3. 3

   A limitation intended to be unalterable and of indefinite duration; a disposition of property which attempts to make it inalienable beyond certain limits fixed or conceived as being fixed by the general law.

4. 4

   An annuity in which the periodic payments begin on a fixed date and continue indefinitely.