semisextile

from The Century Dictionary.

• noun In astrology, an aspect of two planets when they are distant from each other the half of a sextile, or 30 degrees.

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

• noun (Astrol.) An aspect of the planets when they are distant from each other the twelfth part of a circle, or thirty degrees.

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

• noun astrology An aspect of the planets when they are distant from each other the twelfth part of a circle, or thirty degrees.