Biz is sometimes used to refer to the entertainment business, especially pop music or films. It typically refers to the commercial aspect of activities that involve trade, services, or any economic exchanges. From longman dictionary of contemporary english related topics:
How to use biz in a sentence. The term “biz” is an informal abbreviation of the word “business.” it is commonly used in casual conversation to refer to various aspects of business, industry, or a specific occupation. Theatre, business biz /bɪz/ noun [singular] informal a particular type of business, especially one relating to entertainment.
In modern usage, 'biz' is commonly employed in casual conversations,. Idiom be the biz (definition of biz from the cambridge advanced learner's dictionary & thesaurus © cambridge university press) The meaning of biz is business. American heritage® dictionary of the english language, fifth edition.