…signs are divisible, first, according to their modes of being, as objects; secondly, according to the modes of their references to their objects; thirdly, according to the modes of their references to their interpretants. In the first way of dividing them, signs are either qualisigns, or signs that are abstract qualities (in a wide sense), or suisigns, signs that are essentially existent as individual objects or events, or legisigns, signs that [are] general types, laws, or habits.