omnibus vs trolleybus

omnibus and trolleybus both are nouns.

Word	Noun	Adjective	Verb	Adverb
omnibus	Yes	Yes	No	No
trolleybus	Yes	No	No	No

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

omnibus: a vehicle carrying many passengers; used for public transport
trolleybus: a passenger bus with an electric motor that draws power from overhead wires

Other hyponyms of omnibus include minibus, school bus, trackless trolley, trolley coach.

omnibus (noun)	trolleybus (noun)
a vehicle carrying many passengers; used for public transport	a passenger bus with an electric motor that draws power from overhead wires
an anthology of articles on a related subject or an anthology of the works of a single author

omnibus (adjective)	trolleybus (adjective)
providing for many things at once