twin vs fraternal twin

twin and fraternal twin both are nouns.

Word	Noun	Adjective	Verb	Adverb
twin	Yes	Yes	Yes	No
fraternal twin	Yes	No	No	No

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

twin: either of two offspring born at the same time from the same pregnancy
fraternal twin: either of two twins who developed from two separate fertilized eggs

Other hyponyms of twin include dizygotic twin, identical twin, monozygotic twin, monozygous twin, twimbos.

twin (noun)	fraternal twin (noun)
a duplicate copy	either of two twins who developed from two separate fertilized eggs
either of two offspring born at the same time from the same pregnancy

twin (adjective)	fraternal twin (adjective)
being two identical

twin (verb)	fraternal twin (verb)
give birth to twins
grow as twins
bring two objects, ideas, or people together
duplicate or match