pill vs bolus

pill and bolus both are nouns.

Word	Noun	Adjective	Verb	Adverb
pill	Yes	No	No	No
bolus	Yes	No	No	No

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

pill (noun)	bolus (noun)
a dose of medicine in the form of a small pellet	a large pill; used especially in veterinary medicine
something that resembles a tablet of medicine in shape or size	a small round soft mass (as of chewed food)
a contraceptive in the form of a pill containing estrogen and progestin to inhibit ovulation and so prevent conception
something unpleasant or offensive that must be tolerated or endured
a unpleasant or tiresome person