The word hieroglyph is a composite of two Greek words: hieros (sacred) plus glypho (inscriptions) and refers to Egyptian writing. The Egyptians themselves called their writing "mdwt ntr" (god's words). They believed that writing had been developed by the god Thoth and was therefore sacred.
These sites have a good overview of Egyptian hieroglyphics. You can even learn to write in Egyptian:
http://www.omniglot.com/writing/egyptian.htm http://magma.nationalgeographic.com/ngm/egypt/translator.html - write your name in hieroglyphics http://www.ancientscripts.com/egyptian.html - the Egyptian system of hiereoglyphs explained http://www.friesian.com/egypt.htm - pronunciation of ancient Egyptian
You can read more about ancient civilizations including the the Roman Empire here.