fashion industry vs apparel industry

fashion industry and apparel industry both are nouns.

Word	Noun	Adjective	Verb	Adverb
fashion industry	Yes	No	No	No
apparel industry	Yes	No	No	No

As nouns, fashion industry and apparel industry are synonyms defined as:

fashion industry and apparel industry: makers and sellers of fashionable clothing

Other synonyms of fashion industry include fashion business, garment industry, rag trade.

fashion industry (noun)	apparel industry (noun)
makers and sellers of fashionable clothing	makers and sellers of fashionable clothing