taxicab vs minicab

taxicab and minicab both are nouns.

Word	Noun	Adjective	Verb	Adverb
taxicab	Yes	No	No	No
minicab	Yes	No	No	No

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

taxicab: a car driven by a person whose job is to take passengers where they want to go in exchange for money
minicab: a minicar used as a taxicab

Other hyponyms of taxicab include gypsy cab.

taxicab (noun)	minicab (noun)
a car driven by a person whose job is to take passengers where they want to go in exchange for money	a minicar used as a taxicab