Terra or Tellus was a goddess personifying the Earth in Roman mythology. The names Terra Mater and Tellus Mater both mean "Mother Earth" in Latin; Mater is an honorific title also bestowed on other goddesses. The chemical element Tellurium was named after Tellus by Martin Heinrich Klaproth in 1798.
Romans appealed to Terra over earthquakes, and along with the grain goddess Ceres, she was responsible for the productivity of farmland. She was also associated with marriage, motherhood, pregnant women, and pregnant animals. Terra's Greek counterpart is Gaia.
The two words Terra and Tellus are thought to derive from the formulaic phrase tersa tellus, meaning "dry land"; it may also be related to the similar sounding name of the equivalent Etruscan goddess Cel. If this is true, Tellus might be the more ancient version of the name.
According to The Oxford Classical Dictionary, Terra refers to the element earth (one of the four basic elements of earth, air, water, and fire) and Tellus refers to the guardian deity of Earth and by extension the globe itself. Actual classical Latin usage does not necessarily appear to respect this distinction.
A festival for Tellus called the Fordicidia or Hordicidia was held every year on April 15; it involved the sacrifice of pregnant cows and was managed by the pontifex maximus and the Vestal Virgins. The Virgins kept the ashes of the fetal calves until they were used for purification at Parilia.
Two festivals were held in January to mark the end of the winter sowing season, the Sementivae, celebrated in the city, and the Paganalia, celebrated mostly in rural areas. The first part of the Sementivae was held January 24–26 in honor of Tellus, the second part honored Ceres and was held a week later.
A male deity of Earth, Tellumo, was sometimes invoked together with Terra during the rites in her honour