**Thir"teenth`** (?), a. [From Thirteen: cf. AS. *reoteoa*.]

**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.

© Webster 1913.

**Thir"teenth`**, 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.** Mus.

The interval comprising an octave and a sixth.

© Webster 1913.