a.

1. 第二的；第二位的
2. （教育、學校等）中等的[B]
   Virtually all secondary schools are in towns.

   幾乎所有的中學都在城裡。

3. 次要的；從屬的，輔助的[（+to）]
   Many older people still believe that women's careers are secondary.

   許多年歲大一點的人仍然認為婦女的職業生涯並不那麼重要。

4. 第二手的，間接的
5. 【醫】繼發性的；第二期的
6. （顏色）次的，合成的
7. 【語】次要的；次重音的

n.[C]

1. 副手，次要人物；次要的東西
2. 代表，代理人
3. 【美】【橄】第二防線

adj.

1. coming after, less important than, or resulting from something primary.
2. relating to education for children from the age of eleven to sixteen or eighteen.
3. of or denoting the output side of a transformer or other inductive device.
4. Chemistry  (of an organic compound) having its functional group on a carbon atom bonded to two other carbon atoms.
   ▸derived from ammonia by replacement of two hydrogen atoms by organic groups.
5. (Secondary) Geology  former term for Mesozoic.
6. (of a cell or battery) having a reversible chemical reaction and therefore able to store energy.