Nineteenth

Definition:

(a.) Following the eighteenth and preceding the twentieth; coming after eighteen others.
(a.) Constituting or being one of nineteen equal parts into which anything is divided.
(n.) The quotient of a unit divided by nineteen; one of nineteen equal parts of anything.
(n.) The next in order after the eighteenth.
(n.) An interval of two octaves and a fifth.

Compare nineteenth with other words:

nineteenth vs. twentieth