1. [U]量,大小,重量 that which makes it possible to measure things through having number, size, weight, etc.
2. [C][U]数目,数量 number or amount, especially a large one

1. how much there is or how many there are of something that you can quantify

2. an adequate or large amount;

   "he had a quantity of ammunition"
   

3. the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable

1.数量;量
Aquantity is an amount that you can measure or count.

e.g. ...a smallquantity of water.
少量的水
e.g. ...vast quantities of food...
大量食品

2.大量;大宗；大批
Things that are produced or available inquantity are produced or available in large amounts.

e.g. After some initial problems, acetone was successfully produced inquantity...
解决了最初的一些问题之后，终于成功地制造出了大量丙酮。
e.g. But even with those databases, the sheerquantity of data can still cause problems.
可是即便有了那些数据库，数据的数量之大仍然会带来问题。

3.(尤指和质量相对的)数量
You can usequantity to refer to the amount of something that there is, especially when you want to contrast it with its quality.

e.g. ...the less discerning drinker who prefersquantity to quality...
不求质、但求量的不那么识货的饮酒者
e.g. In terms ofquantity, production grew faster than ever before.
从数量上看，产量增长的速度比以往任何时期都要快。

4.未知量;未知数
If you say that someone or something is anunknown quantity, you mean that not much is known about what they are like or how they will behave.

e.g. He is an unknownquantity for his rivals.
对于对手们而言，他是个未知数。

1.quantity：qty; 定额，数量

2.quantity：quant; 数量性