As I am not the only tabby that has this distinct marking, I don't think it stands for Marie (or Mum). But there is a story that it does stand for the Virgin Mary. And Mary is a variant of the name Marie, isn't it? Now, the story goes that there was a cat and her litter of kittens in the stable when Jesus came into the world, and as his mother Mary stroked it, she left the "M" marking on the cat's forehead.
However, there is another version of the origins of the tabby "M" marking. The "M" is said to have been left by the Prophet Mohammed as gratitude to his favourite tabby cat, who was named Muezza. This cat had once saved him from a venomous snake, and legend has it that when the prophet was called to prayer and went to pick up his robe, Muezza was asleep on the sleeve. Rather than disturbing the cat, Mohammed chose to cut off the sleeve and let the cat enjoy his nap instead. When the cat awoke, the prophet marked his forehead with "M" and since that day all tabby cats have that marking.
But cats go back further than that. We know how the Egyptians just loved us and worshipped us (some of those are reborn today, I think, in our own mums and dads and humans. Mum and I certainly shared many lives together, and there is bound to be a few ancient Egyptian ones in there!
The ancient Egyptians called cats "Mau" - probably because it sounds like "meow". So this too can be why us tabbies have this amazing marking!
So what do you think the M stands for?
How about Magnificent? Magical? Mystical?