apparent size of an astronomical body What's the name of the measure of apparent (visible) size of a body? e.g. the Sun and the Moon appear to be roughly the same size, despite the Sun being vastly bigger - because the Moon is much closer. What's this apparent size called?
It's angular diameter (a.k.a angular size or apparent size). This XKCD comic strip shows in an interesting way the angular size of some of the most remarkable objects in the sky: