Yes, it really means M for McDonald s and there really isn t any other meaning McDonald s had intended. Instead, it came to mean something unintentionally by customers, at least according to design consultant and psychologist Louis Cheskin. In the 60s, McDonald s wanted to change their logo but Cheskin insisted on leaving the golden arches. He said it s because customers unconsciously recognize the logo as symbolism of a pair of nourishing breasts (via BBC). Whether we unconsciously believe this or not, Cheskin convinced them and now the logo is one of the most recognizable in the world.