thirty-first

[ thur-tee-furst ]
/ ˈθɜr tiˈfɜrst /

adjective

next after the thirtieth; being the ordinal number for 31.
being one of 31 equal parts.

noun

a thirty-first part, especially of one (1/31).
the thirty-first member of a series.

Example sentences from the Web for thirty-first