The Waning Phase
Waning means getting smaller, to draw to a close; approach an end; diminishing
Waning Moon describes when the moon is getting smaller, decreasing in size
Subsections of the Waning Moon:
Gibbous, Last Quarter and Crescent
Waning Gibbous is right after the full moon when it 99% to 51% illuminated
Last Quarter or Third Quarter (waning) is when the moon is half empty 50% illuminated
Waning Crescent is when the moon is getting smaller (waning) and is a slither in the sky closer to almost becoming invisible but not quite there yet.