I. | ̷ ̷ ̷ ̷| ̷ ̷ adjective
1. : being number 66 in a countable series
the sixty-sixth day
— see number table
2. : being one of 66 equal parts into which something is divisible
a sixty-sixth share of the money
II. noun
1. : number 66 in a countable series
2. : the quotient of a unit divided by 66 : one of 66 equal parts of something
one sixty-sixth of the total