not perishable; not subject to decay; enduring permanently
something that does not perish, or keeps for a long time
non-transient.
Of data or a data structure: not transient or temporary, but remaining in existence after the termination of the program that creates it.
Describing a fractal process that has a positive Brown function
Lasting past maturity without falling off.
Obstinately refusing to give up or let go.
Insistently repetitive.
Indefinitely continuous.