I. | ̷ ̷ ̷ ̷| ̷ ̷ adjective
: being one more than 90 in number
ninety-one years
— see number table
II. pronoun, plural in construction
: ninety-one countable persons or things not specified but under consideration and being enumerated
ninety-one are here
ninety-one were found
III. noun
1. : one and 90 : seven times 13
2.
a. : 91 units or objects
a total of ninety-one
b. : a group or set of 91
3. : the numerable quantity symbolized by the arabic numerals 91