New moon occurs about 14 days after full Moon. This is when the night side of the Moon is turned towards us so it is largely invisible (unless reflected Earthlight is strong.)
A new moon.
That is the first quarter moon which looks like a half moon.
Waxing gibbous phase
waxing gibbous
If tonight the phase of the moon is full when it rises what will be the phase 4 days from now is in the waning gibbous stage.
Full Moon.
At 28 days after a full moon, the moon would be almost but not quite full again. The complete sequence of phases repeats with a period of 29.53 days.
The "waning gibbous" phase lasts from 2 days after the full to 6 days after the full.
First Quarter does.
That is the first quarter moon which looks like a half moon.
A Lunar eclipse occurs only when the moon is in its full moon phase.
Waxing gibbous phase
waxing gibbous
waxing gibbous
waxing gibbous
If tonight the phase of the moon is full when it rises what will be the phase 4 days from now is in the waning gibbous stage.
A full moon.
Full Moon.