Thirteenth

Definition:

(a.) Next in order after the twelfth; the third after the tenth; -- the ordinal of thirteen; as, the thirteenth day of the month.
(a.) Constituting or being one of thirteen equal parts into which anything is divided.
(n.) The quotient of a unit divided by thirteen; one of thirteen equal parts into which anything is divided.
(n.) The next in order after the twelfth.
(n.) The interval comprising an octave and a sixth.

Compare thirteenth with other words:

octave vs. thirteenth