"to grow the segment" means to increase the size or market share of a particular group or category of customers. It refers to the efforts made to attract more people and expand the business within that specific target audience. Full definition
In fact, pizza was named the fastest growing segment of fast - casual restaurants in 2017. (profitableventure.com)
Various studies have found that older adults are the fastest growing segment of online - dating services. (tdberyoza.ru)
The global audiobook industry is currently worth over three billion dollars and is considered to be the fastest growing segment in publishing. (goodereader.com)