Chiefly a neo-pagan and heraldic symbol
The Lunate Cross is usually either used as an heraldic symbol, when it is also called a Croissant, or as a neo-pagan symbol, when it is also called a Moon Cross. (Generally with symbols, the moon is shown as a crescent and the Sun is shown as a circle.)
In heraldry, a lunate moon takes the French name Croissant.
When the Christian crusaders conquered the Turks they took the Crescent, the symbol of Islam, back to western Europe as a war trophy and incorporated it into their insignia. It has appeared in several coats-of-arms since the reign of King Henry III.
In Christianity, the crescent moon can represent virginity, and in particular, the Virgin Mary, Mother of God. (See Crescent Cross.) Four crescents, forming a Lunate Cross, has in itself no additional Christian significance, although it can be viewed as a cross with four stylized Tau patterns.
The Lunate Cross is a neo-pagan symbol, purportedly used by northern European shamans. The concave shape of the moon represents our hidden feminine nature with its various moods. Being a controller of the tides, having a moon in four directions can help balance our moods.
Pagans tell us that an aging goddess is the polarity of the universe and the Crescent Moon is a symbol of this goddess. We are not sure what the 'polarity of the universe' actually means, but it is comforting to know it is feminine.
The moon 'horns' are outward-facing, protecting the cross from evil which might approach from any direction. There are four moons to remind us that the moon has four phases, symbolising protection throughout the month.
And this is all rather strange, because the cross is the antidote for evil. It needs no protection from evil, and even if it did, it's unlikely that the Moon could provide this. (See also why we don't trust astrology.)
Have you ever wondered why, when there's a total solar eclipse, the Sun and Moon appear to be exactly the same size? These two planets, both essential for life on Earth, fit so perfectly that we can only see tiny bits of sunlight streaming through the rugged valleys on the Moon's surface, creating the beautiful and striking diamond ring effect.
This is all due to an amazing coincidence. The Sun is about 400 times as wide as the Moon, but it is also 400 times further away. The two therefore look the same size in the sky - a unique situation among our solar system's eight planets and 166 known moons.
Why is that?
We know that the Moon is very slowly moving away from Earth (about 3.8 cm per year) and this phenomenon will not exist in the future. So why now? Why do we happen to live in the relatively brief period of Earth's history when our Moon just barely blocks the Sun? The chances of this being a random fluke seem remote in the extreme. Yet, what other explanation?
Could it be that God has given us this optical illusion for one simple reason; to get us considering the possibility that it is all part of some Grand Scheme?1 No? Then what other reason could there be? The odds of it being pure 'chance' are too enormous to compute.
See other Crescent Crosses