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geophagy

noun

the practice of eating earthy matter, especially clay or chalk, as in famine-stricken areas.

noun

the practice of eating earth, clay, chalk, etc, found in some primitive tribes
zoology the habit of some animals, esp earthworms, of eating soil

“dirt-eating,” 1850, from Greek *geophagia (according to OED the actual Greek is geotragia), from geo-, comb. form of ge “earth” (see Gaia) + phagein “to eat.”

A diseased appetite … prevails in several parts of Alabama, where they eat clay. I heard various speculations on the origin of this singular propensity, called ‘geophagy’ in some medical books. [Lyell, “Second Visit to U.S.,” 1850]

Cf. also pica (n.2).

The eating of earthy substances, such as clay or chalk, that is practiced as a custom or for dietary or subsistence reasons.dirt-eating