Online Encyclopedia of Western Signs and Ideograms Symbols.com

Symbol 28:8

2807

28:8 · The diagonally placed square has no particular spectrum of meaning as far as we know. It is found engraved in the cave of Marsoulas in prehistoric times, but there are no clues as to what it might have meant. The sign is the symbol for the suit of diamonds in a pack of cards. Diamonds are usually associated with courage and daring.
    The British hobos made use of 2807 to mean here live generous people, but behave well, show them respect, and take nothing for granted. In the French hobo or gypsy sign system 2807 means here nobody lives.
    In meteorology it can sometimes signify clear air and in chemistry, soft soap. It has been used in biological contexts for an individual of unknown or not stated sex.
    In North America, Japan and Australia (at least) it is a road sign meaning danger ahead.
    Compare with 3905, one of the alchemists' signs for sulphur and also one of the signs for the asteroid Pallas.