em vs pica

em and pica both are nouns.

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

As nouns, em and pica are synonyms defined as:

Other synonyms of em include pica em.

em (noun)	pica (noun)
a quad with a square body	a linear unit (1/6 inch) used in printing
a linear unit (1/6 inch) used in printing	an eating disorder, frequent in children, in which non-nutritional objects are eaten persistently