ˈeighˈteenth

/ ˈeɪˈtiːnθ /

adjective

1. usually prenominal
   1. coming after the seventeenth in numbering or counting order, position, time, etc; being the ordinal number of eighteen: often written 18th
   2. ( as noun )

      come on the eighteenth

noun

1. 1. one of 18 approximately equal parts of something
   2. ( as modifier )

      an eighteenth part

2. the fraction that is equal to one divided by 18 ( 1 18 )