fifteenth
/ˈfɪfˈtiːnθ/ordinal number
1- constituting number fifteen in a sequence; 15th第十五（个）：
August the fifteenth
8月15日
the fifteenth century
15世纪
on the fifteenth floor.
在15楼。
1.1
a fifteenth/one fifteenth
each of fifteen equal parts into which something is or may be divided十五分之一。
1.2
- an organ stop sounding a register of pipes two octaves (fifteen notes) above the diapason（管风琴的）十五度音栓。