Eighteenth

Definition:

(a.) Next in order after the seventeenth.
(a.) Consisting of one of eighteen equal parts or divisions of a thing.
(n.) The quotient of a unit divided by eighteen; one of eighteen equal parts or divisions.
(n.) The eighth after the tenth.

Compare eighteenth with other words:

eighteenth vs. octodecimo

eighteenth vs. nineteenth

birthday vs. eighteenth

eighteenth vs. party

eighteen vs. eighteenth