twin vs monozygous twin

twin and monozygous twin both are nouns.

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

As nouns, monozygous twin is a hyponym of twin; that is, monozygous 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
monozygous twin: either of two twins developed from the same fertilized ovum (having the same genetic material)

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

twin (noun)	monozygous twin (noun)
a duplicate copy	either of two twins developed from the same fertilized ovum (having the same genetic material)
either of two offspring born at the same time from the same pregnancy

twin (adjective)	monozygous twin (adjective)
being two identical

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