I. | ̷ ̷ ̷ ̷| ̷ ̷ adjective
1. : being number 99 in a countable series
the ninety-ninth day
— see number table
2. : being one of 99 equal parts into which something is divisible
a ninety-ninth share of the money
II. noun
1. : number 99 in a countable series
2. : the quotient of a unit divided by 99 : one of 99 equal parts of something