plural thirties
1
: a number equal to three times 10 see Table of Numbers
2
thirties plural
: the numbers 30 to 39
specifically
: the years 30 to 39 in a lifetime or century
3
: a sign of completion : end
—usually written 30
wrote thirty on the last page of the story
4
: the second point scored by a side in a game of tennis
thirty
adjective
thirty
pronoun, plural in construction
thir·ti·eth
ˈthər|t|ēə̇th
ˈthə̄|,
ˈthəi|,
|t|,
|iə̇th
1
: being number 30 in a countable series
the thirtieth day
see Table of Numbers
2
: being one of 30 equal parts into which anything is divisible
a thirtieth share of the money
"
plural -s
1
: number 30 in a countable series
the thirtieth of the month
2
: the quotient of a unit divided by 30 : one of 30 equal parts of anything
one thirtieth of the total
Cite this Entry
“Thirty.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thirty. Accessed 27 Aug. 2026.
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