wane

To decrease gradually in size, number, strength, or intensity.

To show a progressively smaller illuminated area, as the moon does in passing from full to new.

To approach an end.

The act or process of gradually declining or diminishing.

A time or phase of gradual decrease.

The period of the decrease of the moon’s illuminated visible surface.

A defective edge of a board caused by remaining bark or a beveled end.

(on the wane) In a period of decline or decrease.

To decrease; be diminished: applied particularly to the periodical lessening of the illuminated part of the moon: opposed to wax.