Chthonophagia

\Chthon`o*pha"gi*a\, Chthonophagy \Chtho*noph"a*gy\, n. [NL. chthonophagia; Gr. ?, ?, earth + ? to eat.]

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

Webster’s Revised Unabridged Dictionary (1913)