orbital plane n.
The orbital surface of the maxilla that lies perpendicular to the Frankfort plane at the orbitale.
That he and his brother had originally elected to come into this system along its orbital plane had been a mixed blessing.
Mercury rotates synchronously with its revolution—that is, once in 88 days—on an axis sensibly perpendicular to its orbital plane.
Huddled up to resemble stray fragments, they curved out of the Belt—toward the Pole Star, north of its orbital plane.