eighty-third I. \| ̷ ̷ ̷ ̷| ̷ ̷\adjective 1.: being number 83 in a countable series < the eighty-third day > — see number table 2.: being one of 83 equal parts into which something is divisible < an eighty-third share of the money > II. noun 1.: number 83 in a countable series 2.: the quotient of a unit divided by 83 : one of 83 equal parts of something < one eighty-third of the total >