subindustry
noun
sub·in·dus·try ˌsəb-ˈin-(ˌ)də-strē 
variants or sub-industry
plural subindustries or sub-industries
: a lesser industry
especially : one derived from or dependent on a larger industry
a technology subindustry
A whole subindustry of agents and publicists has sprung up to manage everything from a chef's media appearances to his hairstyle. 
Lisa Abend
Lisa Abend 
Word History
First Known Use
1868, in the meaning defined above