adj
noun
Freq #70265
Meanings
-
1
adj
coming next after the twenty-ninth in position
They celebrated their thirtieth anniversary.
-
2
noun
position 30 in a countable series of things
They celebrated their thirtieth anniversary.
Etymology
From earlier thirteth, from Middle English thrittithe, threttiþe, thrittyde, from Old English þrītigoþa; equivalent to thirty + -eth. For the modern form, see the etymological notes at twentieth.