(idiomatic) Not being used; temporarily unavailable or suspended; on hold. / Of an entertainment normally performed on a stage: performed by ice skaters as an ice show.

(astronomy, physics) Either of two torus-shaped areas of high-energy charged particles which partly surround Earth, trapped by its magnetic field. The areas are characterised by intense radiation. ...

(ecology) The modification of an environment by invasion of microbes

Preventing or countering degradation.