Webster’s Revised Unabridged Dictionary · 1913
Dextral
Dex′tral (dĕks′tral), a. [From Dexter.] Right, as opposed to sinistral, or left.
Dextral shell (Zoöl.), a spiral shell the whorls of which turn from left right, or like the hands of a watch when the apex of the spire is toward the eye of the observer.