first appearance vs unveiling

first appearance and unveiling both are nouns.

Word	Noun	Adjective	Verb	Adverb
first appearance	Yes	No	No	No
unveiling	Yes	No	No	No

As nouns, first appearance and unveiling are synonyms defined as:

Other synonyms of first appearance include debut, entry, introduction, launching.

first appearance (noun)	unveiling (noun)
the act of beginning something new	the act of beginning something new
	putting on display for the first time