* Terrestrial: Relating to the Earth or its inhabitants.
* Terrain: The physical features of an area of land.
* Terracotta: A type of reddish-brown earthenware.
* Terrace: A level area of ground, often used for gardening.
* Territory: An area of land under the control of a particular state or ruler.
* Extraterrestrial: Originating or existing outside the Earth.
These are just a few examples. You can find many other words related to "terra" if you look at their etymology.