It can be used in various contexts:
* Earth as a planet: "La Tierra es un planeta en el sistema solar." (Earth is a planet in the solar system.)
* Land, soil: "La tierra está seca." (The land is dry.)
* Ground: "Cayó al suelo y se golpeó la cabeza." (He fell to the ground and hit his head.)
* Country, nation: "Ella nació en la tierra de los sueños." (She was born in the land of dreams.)
It's important to note that "tierra" is a feminine noun in Spanish, so you would use the feminine articles "la" or "una" before it.