chickenpox vs varicella

chickenpox and varicella both are nouns.

Word	Noun	Adjective	Verb	Adverb
chickenpox	Yes	No	No	No
varicella	Yes	No	No	No

As nouns, chickenpox and varicella are synonyms defined as:

chickenpox and varicella: an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body

chickenpox (noun)	varicella (noun)
an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body	an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body