Merriam-Webster Collegiate Dictionary - dextral

 adjective  Date: 1646 of or relating to the right ; inclined to the right: as  a. right-handed 3  b. of a gastropod shell having the whorls coiling clockwise down the spire when viewed with the apex toward the observer and having the aperture situated on the right of the axis when held with the spire uppermost and with the aperture opening toward the observer — compare sinistral