pica vs geophagy

pica and geophagy both are nouns.

Word	Noun	Adjective	Verb	Adverb
pica	Yes	No	No	No
geophagy	Yes	No	No	No

As nouns, geophagy is a hyponym of pica; that is, geophagy is a word with a more specific, narrower meaning than pica:

pica: an eating disorder, frequent in children, in which non-nutritional objects are eaten persistently
geophagy: eating earth, clay, chalk; occurs in some primitive tribes, sometimes in cases of nutritional deficiency or obsessive behavior

Other hyponyms of pica include geophagia.

pica (noun)	geophagy (noun)
a linear unit (1/6 inch) used in printing	eating earth, clay, chalk; occurs in some primitive tribes, sometimes in cases of nutritional deficiency or obsessive behavior
an eating disorder, frequent in children, in which non-nutritional objects are eaten persistently