a.

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

   你所上的課對你的在職訓練是有輔助性的，你將來就知道了。

2. 從屬的；有關的

adj.

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

n.