eightieth

adjective

1. next after the seventy-ninth; being the ordinal number for 80.
2. being one of 80 equal parts.

noun

3. an eightieth part, especially of one (1/80).
4. the eightieth member of a series.

adjective

1. (usually prenominal)
   1. being the ordinal number of eighty in numbering or counting order, position, time, etc: often written 80th
   2. (as noun)the eightieth in succession

noun

2. 1. one of 80 approximately equal parts of something
   2. (as modifier)an eightieth part
3. the fraction equal to one divided by 80 (1/80)