What do you mean by women's group 3i era?

The five-generation women's group has three pillars. 3i refers to three five-generation women's groups, namely Itzy, Gidle and Izone. The 3i era refers to the situation that the peaks of three five-generation women's groups have merged into three pillars. The fifth generation women's group refers to the group that debuted after 20 18, and is called the fifth generation group.