The continental crust is the outermost layer of the Earth's surface that makes up the continents. It is composed mainly of rock types such as granite, and has a thickness of about 25-90 km. There are several synonyms that can be used for continental crust, including sial, granitic crust, and upper crust. "Sial" stands for silicon and aluminum, which are the two major elements found in continental crust. "Granitic crust" refers to the dominant rock type, granite, that makes up the continental crust. Lastly, "upper crust" describes the uppermost layer of the Earth's crust, which includes both the continental and oceanic crust.