a.

1. 确定的；确实的
   There is positive proof that he did it.

   有确凿的证据证明他做了这件事。

2. 确信的；有自信的[F][（+of/about）][+（that）]
   Are you positive that you saw him?

   你肯定你看到他吗？

3. 绝对的
4. 积极的，建设性的
   He has a positive attitude towards life.

   他对生活持有积极的态度。

5. 真实的；实际的；实在的[Z][B]
   Light is a positive thing; darkness is only the absence of light.

   光是确实存在的东西；黑暗只是没有光。

6. 【口】完全的，纯粹的[Z][B]
   He is a positive fool.

   他是一个十足的傻瓜。

7. 【语】原级的[Z]
   "Good" is the positive form of the adjective, "better" is the comparative.

   “好”是该形容词的原级，“更好”是比较级。

8. 【数】正的[Z]
   Five is a positive number.

   五是正数。

9. 【物】正的，阳性的[Z]
10. 【摄】正片的，正像的[Z]
11. 【医】阳性的
    The blood tests were positive.

    验血结果呈阳性。

n.[C]

1. 实在的事物
2. 正面
3. 【语】原级[the S]
4. 【数】正数
5. 【摄】正片，正像
6. （电池的）阳极

adj.

1. consisting in or characterized by the presence rather than the absence of something.
   ▸expressing or implying affirmation, agreement, or permission.
   ▸ [often in combination] having a specified substance or condition:

   HIV-positive.
2. constructive, optimistic, or confident.
3. with no possibility of doubt; certain.
4. (of a quantity) greater than zero.
5. containing, producing, or denoting the kind of electric charge opposite to that carried by electrons.
6. (of a photographic image) showing light and shade or colours true to the original.
7. Grammar  (of an adjective or adverb) expressing a quality in its basic, primary degree. Contrasted with comparative and superlative.
8. chiefly Philosophy  dealing only with matters of fact and experience. See also positivism (sense ¹).

n.

1. a desirable quality or attribute.
2. a positive photographic image, especially one printed from a negative.