Chthonophagia is a rare word that refers to the act of consuming soil or earth. There are several synonyms for this unusual term that can be used in place of chthonophagia depending on the context in which it is used. Some of the other words that can be used are geophagy, terraphagy, and terrephagia. These terms all describe the same behavior of eating soil or earth. While this may seem like an odd behavior, it is actually quite common in some cultures and has been practiced for centuries. People may consume soil for a variety of reasons, such as to obtain minerals or as a remedy for digestive issues.