—v.i. 1. to decrease in strength, intensity, etc.: Daylight waned, and night came on. Her enthusiasm for the cause is waning. 2. to decline in power, importance, prosperity, etc.: Colonialism began to wane after World War II. 3. to draw to a close; approach an end: Summer is waning. 4. (of the moon) to decrease periodically in the extent of its illuminated portion after the full moon. Cf. wax2 (def. 2).
—n. 1. a gradual decrease or decline in strength, intensity, power, etc.
2. the drawing to a close of life, an era, a period, etc.
3. the waning of the moon.
4. a period of waning.
5. a defect in a plank or board characterized by bark or insufficient wood at a corner or along an edge, due to the curvature of the log.
6. on the wane, decreasing; diminishing: The popularity of that song is on the wane.