The real name for this full phase is a Perigee Moon. It’s when the Moon in its orbit about the Earth is at its closest point. The Moon does not orbit the Earth in a perfect circle but in an ellipse (like a squashed circle) so it can be up to 50,000km closer at Perigee (which is why it appears larger in the sky) or up to 50,000 kms further away from us here on Earth, which is called Apogee.