a.

1. 补助的；补充的；辅助的
   The courses you took are ancillary to your on-the-job training, as you shall see.

   你所上的课对你的在职训练是有辅助性的，你将来就知道了。

2. 从属的；有关的

adj.

1. providing support to the primary activities of an organization.
2. additional but less important; subsidiary.

n.