2 entries under this word

Thirteenth

Thĭr'teenth, a.

adjective

a. [From thirteen; A-S. threóteódha.]

Next in order after the twelfth; the third after the tenth; — the ordinal of thirteen; as, the thirteenth day of the month.
Constituting, or being, one of thirteen equal parts into which any thing is divided.

noun

n. 1. The quotient of a unit divided by thirteen; one of thirteen equal parts. 2. (Mus.) The interval comprising an octave and a sixth.