英汉词典

1. 第九
    The ninth item in a series is the one that you count as number nine.

    e.g. ...January the ninth.
           1月9日
    e.g. ...students in the ninth grade.
           9年级学生

2. 九分之一
    A ninth is one of nine equal parts of something.

    e.g. In Brussels the dollar rose by a ninth of a cent...
           在布鲁塞尔美元升值了1/9美分。
    e.g. What you see is only the tip. Eight ninths of it is under the sea.
           你看到的只是一角，8/9的部分在海里。