DECREMENT, noun

1. Decrease; waste; the state of becoming less gradually.

Rocks and mountains suffer a continual decrement

2. The quantity lost by gradual diminution, or waste.

3. In heraldry, the wane of the moon.

4. In crystalography, a successive diminution of the lamens of molecules, applied to the faces of the primitive form, by which the secondary forms are supposed to be produced.