unveiling vs first appearance

unveiling and first appearance both are nouns.

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

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

Other synonyms of unveiling include debut, entry, introduction, launching.

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