When the Daniel and the others first reach the city they are taken to the eye symbol on the large disk. He then says "it's the Eye of Ra", but in actual egyptian mythology that eye represents the god horus and other variations of him (i.e. ra was horus's grandfather)
*Actually*, the "Eye of Ra" is correct. In older Egyptian legends, the symbol used in "Stargate" was the right eye of Ra, representing the sun. The reverse of this symbol, the left eye, represented the moon. It wasn't until much later (the Middle Kingdom, perhaps?) that the right eye became associated with Horus.
In Egyptian mythology there is a story that tells of a fight between Horus and one of the other gods (I can't remember which one). In the fight Horus loses his eye. The eye symbolizes Horus. The eye is supposed to protect anything behind it, that is why you see it on ancient tombs and boats.
Dragonace - Around 196 B.C., the Egyptians foresaw your inability to learn a second language and tried to help - three times. They left a note praising their king, Ptolemy V, in hieroglyphic, once in demotic, and once in Greek (the Rosetta Stone). Apparently they failed.
From 'http://altreligion.about.com/library/glossary/symbols/bldefseyeofhorus.htm':
"Designed to resemble the eye of a falcon, this symbol is called the Eye of Ra or Eye of Horus represents the right eye of the Egyptian Falcon God Horus. As the udjat (or utchat), it represented the sun, and was associated with the Sun God Ra (Re)."
Actually, we don't really know the meanings of any Egyptian symbols, we can only relate them to what we now know. But in the time of the pyramids and the people who lived there could have known everything different, so for all we know the eye could be their pet dog.