biz vs line of work

biz and line of work both are nouns.

Word	Noun	Adjective	Verb	Adverb
biz	Yes	No	No	No
line of work	Yes	No	No	No

As nouns, line of work is a hypernym of biz; that is, line of work is a word with a broader meaning than biz:

Other hypernyms of biz include business, job, line, occupation.

biz (noun)	line of work (noun)
your occupation or line of work	the principal activity in your life that you do to earn money