- noun the ability of a chemical to remain active without breaking down in the environment for a period of time
- noun the ability to grow for several seasons
- noun the act of continuing to do something and not giving up
- The length of time that the phosphors on the screen of a CRT glow after the electron beam has passed.
- The property or tendency of certain materials, especially phosphors, to glow after the excitation has passed.
- noun the existence of a medical condition for a considerable time