What is a "Civilization"?

Civilization refers to when a group of people have a formal gathering place, a system of writing, and a city. The Aztecs were an ancient civilization that once controlled the heart of Mexico. The Aztec language was Nahuatl and they formally gathered at Aztec temple pyramids. The Aztecs did many things that today people would think was vary savage like. One of those savage attributes they had was human sacrifice during religious ceremonies. The question for me is would a civilization like this be looked at as a "Civilization" in todays world?