Full Definition of SITE. 1. a: the spatial location of an actual or planned structure or set of structures (as a building, town, or monuments) b: a space of ground occupied or to be occupied by a building.
Long story short - continental crust is thicker because is less dense, and it is less dense because it's composed mostly of quartz and feldspars, both having density around 2.6 g/cm3, whereas oceanic crust is made up by slightly denser Ca feldspar called plagioclase as well as pyroxenes and olivine, both having density above 3 g/dm3.
The oldest age for this type of crust is around 200 million years old versus the four billion year old continental crust. In addition to this, oceanic crusts are only around 4.3 miles thick (7 kilometers) as compared to the continental crust, which is between 6 to 43 miles (10 to 70 kilometers) thick.