substyle

from The Century Dictionary.

• noun In dialing, the line on which the style or gnomon stands, formed by the intersection of the face of the dial with the plane which passes through the gnomon.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Dialing) A right line on which the style, or gnomon, of a dial is erected; being the common section of the face of the dial and a plane perpendicular to it passing through the style.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A right line on which the style, or gnomon, of a dial is erected, being the common section of the face of the dial and a plane perpendicular to it passing through the style.