rumination vs mastication

rumination and mastication both are nouns.

Word	Noun	Adjective	Verb	Adverb
rumination	Yes	No	No	No
mastication	Yes	No	No	No

As nouns, mastication is a hypernym of rumination; that is, mastication is a word with a broader meaning than rumination:

rumination: (of ruminants) chewing (the cud)
mastication: biting and grinding food in your mouth so it becomes soft enough to swallow

Other hypernyms of rumination include chew, chewing, manduction.

rumination (noun)	mastication (noun)
regurgitation of small amounts of food; seen in some infants after feeding	biting and grinding food in your mouth so it becomes soft enough to swallow
(of ruminants) chewing (the cud)
a calm, lengthy, intent consideration