ADJ
（人、觀點、行為）主流的，傳統的，約定俗成的
You can use mainline to describe people, ideas, and activities that belong to the most central, conventional, and normal part of a tradition, institution, or business.
例句
We observe a striking shift away from a labor theory among all mainline economists...
我們發現在主流經濟學家中間出現了一種偏離勞動理論的顯著變化。
Mainline feminism was arguing for the inherent beauty of the natural woman.
主流女權主義思想倡導女性天生的自然美。