trebly

adj

1. Having treble, or high-pitched, qualities.

   “With the room so bare, Ivret’s voice sounded different, trebly echoes ringing off her sibilants.”

adv

1. (archaic, not-comparable)Three times, thrice
2. (not-comparable)To three times the extent or degree; triply.

   “For my part, I must do my best to save this fellow's trebly worthless life; Jim, you get me a basin.”

   “The task was made trebly difficult, however, by the badly run-down condition in which the railways of Britain had been unavoidably left at the end of the war in 1945, […].”