meconium vs feces

meconium and feces both are nouns.

Word	Noun	Adjective	Verb	Adverb
meconium	Yes	No	No	No
feces	Yes	No	No	No

As nouns, feces is a hypernym of meconium; that is, feces is a word with a broader meaning than meconium:

meconium: thick dark green mucoid material that is the first feces of a newborn child
feces: solid excretory product evacuated from the bowels

Other hypernyms of meconium include BM, dejection, faecal matter, faeces, fecal matter, ordure, stool.

meconium (noun)	feces (noun)
thick dark green mucoid material that is the first feces of a newborn child	solid excretory product evacuated from the bowels