n. - The quality or state of being perpetual; as, the perpetuity of laws.
n. - Something that is perpetual.
n. - Endless time.
n. - The number of years in which the simple interest of any sum becomes equal to the principal.
n. - The number of years' purchase to be given for an annuity to continue forever.
n. - A perpetual annuity.
n. - Duration without limitations as to time.
n. - The quality or condition of an estate by which it becomes inalienable, either perpetually or for a very long period; also, the estate itself so modified or perpetuated.