the ordinal number corresponding to the number 30

तीसवाँ

English Usage: She finished in thirtieth place in the race.

Hindi Usage: उसे दौड़ में तीसवाँ स्थान मिला।

being the ordinal number of 30 in a sequence

तीसवाँ

English Usage: This is the thirtieth anniversary of their marriage.

Hindi Usage: यह उनके विवाह की तीसवाँ सालगिरह है।