Fortieth /(?)/

For·ti·eth

Fortieth

a.
  1. Following the thirty-ninth, or preceded by thirty-nine units, things, or parts.
  2. Constituting one of forty equal parts into which anything is divided.

Fortieth

n.
  1. One of forty equal parts into which one whole is divided; the quotient of a unit divided by forty; one next in order after the thirty-ninth.