The quality of being perpetual.

(physics) The motion of some hypothetical device that continues forever with no external input of energy, in violation of the laws of thermodynamics.

A license with no expiration date.

Causing itself to continue to exist.

(finance) A bond with no maturity date, paying coupons forever.

plural of perpetual bond

(marketing) A marketing strategy in which a maker of computer software or hardware repeatedly launches early versions of new products as a product development feedback method.

plural of perpetual check

(chess) A draw forced by one player by putting the opponent's king in a potentially infinite series of checks.

An act or state of something causing itself to continue to exist.