The correct term is a 'WANING Moon.
From Full Moon to the next New Moon, the moon is said to be WANING.
From Full Moon to Last Quarter is it a WANING GIBBOUS Moon.
From Last Quarter to the next New Moon it is a WANING CRESCENT Moon.
In very clear weather you will see the waning crescent Moon, with the 'ghost' of the Moon's full circle. In old lore it is said to be 'The old moon, with the new moon in her arms'.
waning
Waning
When the moon appears to be shrinking, it is said to be waning. This phase occurs as the amount of illuminated surface visible from Earth is decreasing. It gradually transitions from a full moon to a new moon.
A crescent moon is growing when it transitions from a new moon to a first quarter moon, and shrinking when it transitions from a last quarter moon to a new moon. The growth or shrinkage of the crescent moon is a result of the changing angles between the sun, moon, and Earth during the moon's orbit.
Waning.
we don't know yet but the moon is shrinking
waning
Waning
When the moon appears to be shrinking, it is said to be waning. This phase occurs as the amount of illuminated surface visible from Earth is decreasing. It gradually transitions from a full moon to a new moon.
A crescent moon is growing when it transitions from a new moon to a first quarter moon, and shrinking when it transitions from a last quarter moon to a new moon. The growth or shrinkage of the crescent moon is a result of the changing angles between the sun, moon, and Earth during the moon's orbit.
Waning.
The moon is in its waning (shrinking) gibbous phase for roughly the week after the Full Moon.
It is said to be waning, and waxing when the moon's light is increasing.
This happens about once a month. We call this the "third quarter" phase of the moon.
Nothing whatsoever. The Moon is apparently shrinking a tiny bit, because the core of the Moon has been cooling and shrinking - but the net effect, from 250,000 miles away, is precisely zero. As long as the mass of the Moon stays the same (and it is) and the ORBIT of the Moon remains the same (and it is!) then the gravitational force on the tides is entirely unchanged.
waxing is when it's growing, waning is when it's shrinking
No. The MASS of the Moon isn't changing; it's just "shrinking" a VERY little.