1. usa：united states of american; 美国

2. usa：united states army; 美军

3. usa：unites states army; 美国陆军

4. usa：united soccer association; 联合足球协会

1. 美国
The USA is an abbreviation for (缩略=) the United States of America .

e.g. In the USA you can ring Social Security or the Department of Welfare and ask what help is available.
在美国，你可以致电社会保障部或福利部询问能得到何种帮助。

2. 美国陆军
USA is an abbreviation for (缩略=) United States Army .