1. fifteenth - coming next after the fourteenth and just before the sixteenth in position. 15th. ordinal - being or denoting a numerical order in a series; "ordinal numbers"; "held an ordinal rank of seventh"

What does 30t mean?

thirtieth | American Dictionary

(in the position of) the number 30 in a series; 30th: Ashley's having a party to celebrate her thirtieth birthday. [ C ] Today is the thirtieth of September. A thirtieth is one of thirty equal parts of something.

What is the meaning of seventeenth?

/ˌsev·ənˈtinθ/ (in the position of) the number 17 in a series; 17th: the seventeenth century. [ C ] Her birthday is on the seventeenth. A seventeenth is one of 17 equal parts of something.