million是百万的意思，billion是十亿的意思。
拓展资料
million
1、(abbr. m) 一百万
1 000 000
a population of half a million
五十万人口
tens of millions of dollars
数千万元
It must be worth a million (= pounds, dollars, etc.)
它一定值一百万。
a, one, two, several, etc. million 时，million 后面不加 s。若前面没有数目或数量，可用 millions (of ...)。million 和 millions 均用复数动词，指明金额除外：Four million (people) were affected. Two million (pounds) was withdrawn from the account.
2、a million
(or ) millions (of…)
(informal) 大量
a very large amount
I still have a million things to do.
我还有很多很多的事情要做。
There were millions of people there.
那里人山人海。
He made his millions (= all his money) on currency deals.
他的万贯家财都是通过外汇交易得到的。
billion
1、(abbr. bn) 十亿
1 000 000 000; one thousand million
Worldwide sales reached 2.5 billion.
全球销售额达到了25亿。
half a billion dollars
五亿元
They have spent billions on the problem (= billions of dollars, etc.) .
他们花了几十亿元解决这个问题。
There are more examples of how to use numbers at the entry for hundred . 说 a, one, two, several, etc. billion 时， billion后面不加s。若前面没有数目或数量，可用billions (of...)。除非指金额，billion和billions均用复数动词：预计全世界将有20亿人观看这场比赛。从该账户提取了20亿元。更多数词用法示例见hundred词条。
2、a billion
(or ) billions
(informal) 数以十亿计；大量
a very large amount
Our immune systems are killing billions of germs right now.
我们的免疫系统正在杀死数以十亿计的细菌。
3、(old-fashioned, BrE) 一万亿
1 000 000 000 000; one million million