an eye surrounded by a square what does it mean

Greetings! I believe you are referring to the Eye of Horus which is also called the Eye of the moon or th Eye of Ra. This symbol was used in ancient Egypt for harnessing the protection and power from the deities, Horus and Ra. In Egyptian mythology, Horus was the son of Goddess Isis and God Osiris. At that time, people believed that this eye of Horus possessed lucky powers because it was taken away from him and then restored back to his body magickally. It has been used as a good luck symbol since then. Horus was a sun god who sometimes took the form of a falcon and so the eye is depicted similar to that of a falcon. The teardrop under the eye is also similar to the markings on a falcon. At times, this symbol is used to represent the Sun god. To represent the Moon, the mirror image of this symbol is used. Ancient Egyptians believed that this symbol represented everlasting strength and immortality. Many mummies were found with this marking on them. Jewelry with this symbol has become quite popular. People who believe that they are cursed or under the spell of black magic use such talismans or amulets to ward off the malevolent energies sent towards them. These jewelry can be in the form of pendants, ring or bracelets. As you can see, this symbol is just one of the ancient pagan symbols that are used as good luck charms. Brightest Blessings!