a.

1. 首要的，主要的
   A primary cause of Tom's failure is his laziness.

   懶惰是湯姆失敗的主要原因之一。

2. 初級的，初等的；基層的[Z][B]
   I started primary school when I was 5 years old.

   我五歲時開始讀小學。

3. 最初的；原始的[Z][B]
   The historian searched for primary sources of information about the past.

   歷史學家尋找有關過去的原始資料來源。

4. 基本的；本來的[Z][B]
   The primary meaning of the word isn't used now, but you can look it up in a big dictionary.

   這個字的本義現在不用了，但你可以在大字典裡查到。

n.[C]

1. （次序，品質等）居首位的事物
2. 原色
3. 【主美】候選人選拔會；初選
   We lost the New Hampshire primary.

   我們在新罕布夏州的初選失利了。

adj.

1. of chief importance; principal.
2. earliest in time or order.
   ▸ (Primary) Geology  former term for Palaeozoic.
3. not caused by or based on anything else.
4. chiefly Brit. relating to or denoting education for children between the ages of about five and eleven.
5. of or denoting the input side of a transformer or other inductive device.
6. Chemistry  (of an organic compound) having its functional group on a carbon atom bonded to no more than one other carbon atom.
   ▸derived from ammonia by replacement of one hydrogen atom by an organic group.

n.

1. (in the US) a preliminary election to appoint delegates to a party conference or to select the candidates for a principal, especially presidential, election.
2. Astronomy  the body orbited by a smaller body.