chthonophagia

from The Century Dictionary.

• noun In pathology, a morbid propensity for eating dirt; cachexia Africana.

from the GNU version of the Collaborative International Dictionary of English.

• noun A disease characterized by an irresistible desire to eat earth, observed in some parts of the southern United States, the West Indies, etc.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun pathology A disease characterized by the impulsive consumption of dirt, observed in some parts of the southern United States as well as the West Indies.