One of the largest feeders for high school math competitions—including those that eventually lead to the IMO— is a middle school program called Math Counts.
2017年6月六级真题（第三套）阅读 Section B
柯林斯高阶英汉双解学习词典释义
ADJ
汇入主干道的;汇入干流的;(铁路)支线的
A feeder road, railway, or river is a smaller one that leads to a more important one.