WordReference Random House Unabridged Dictionary of American English © 2017
thir•ty-one  (thûrtē wun),USA pronunciation n. 
  1. a cardinal number, 30 plus 1.
  2. a symbol for this number, as 31 or XXXI.
  3. a set of this many persons or things.

  1. amounting to 31 in number.

'thirty one' also found in these entries:

Word of the day: spare | scale


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