Thirteenth /(thẽr"tēnth`)/

Thir·teenth

Thirteenth

a.
  1. Next in order after the twelfth; the third after the tenth; -- the ordinal of thirteen; as, the thirteenth day of the month.
  2. Constituting or being one of thirteen equal parts into which anything is divided.

Thirteenth

n.
  1. The quotient of a unit divided by thirteen; one of thirteen equal parts into which anything is divided.
  2. The next in order after the twelfth.
  3. The interval comprising an octave and a sixth. (Mus.)