Thirtieth (adjective)

Being the ordinal form of the number 30; coming after the twenty-ninth and before the thirty-first.

Origin:

Formed from the cardinal number "thirty" with the suffix "-eth" which is used to indicate ordinal numbers.

Examples:

1. Today is the thirtieth of June.
2. He was born on the thirtieth of May.
3. The thirtieth is the last day of the month.
4. I will see you on the thirtieth of this month.
5. The thirtieth anniversary is a significant milestone.