Thirtieth /(?)/

Thir·ti·eth

Thirtieth

a.
  1. Next in order after the twenty-ninth; the tenth after the twentieth; -- the ordinal of thirty; as, the thirtieth day of the month.
  2. Constituting or being one of thirty equal parts into which anything is divided.

Thirtieth

n.
  1. The quotient of a unit divided by thirty; one of thirty equal parts.