adj

• Befitting a monarch.
  "The children to whom I acted as cicerone almost screamed with glee as they saw the four-and-twenty blackbirds emerging from the pie-crust in front of the astonished King; and when the climax of the inconsequential story was reached, by way of the regal counting house and the “reginal” parlour, and a blackbird (presumably one of the four-and-twenty that had been temporarily immured in the pie) was seen about to revenge himself on the innocent nose of the guiltless laundry-maid, a veritable climax of enthusiasm was reached."

noun

• (music) A small, portable organ whose sound is produced by brass beating reeds without amplifying resonators. Its tone is keen and rich in harmonics. The regal was common in the 16th and 17th centuries, and has been revived for the performance of music from those times.
• (music) An organ stop of the reed family, furnished with a normal beating reed, but whose resonator is a fraction of its natural length. In the 16th and 17th centuries these stops took a multitude of forms. Today only one survives that is of universal currency, the so-called vox humana.