Wordnet 3.0
ADJECTIVE (2)
1. 
 of or relating to an orbit; 
- Example: "orbital revolution"- Example: "orbital velocity"2. 
 of or relating to the eye socket; 
- Example: "orbital scale"- Example: "orbital arch"
The Collaborative International Dictionary of English v.0.48:
Orbital \Or"bit*al\, a.
   Of or pertaining to an orbit. "Orbital revolution." --J. D.
   Forbes.
   [1913 Webster]
   Orbital index (Anat.), in the skull, the ratio of the
      vertical height to the transverse width of the orbit,
      which is taken as the standard, equal to 100.
      [1913 Webster]
WordNet (r) 3.0 (2006):
orbital
    adj 1: of or relating to an orbit; "orbital revolution";
           "orbital velocity"
    2: of or relating to the eye socket; "orbital scale"; "orbital
       arch"
Moby Thesaurus II by Grady Ward, 1.0:
20 Moby Thesaurus words for "orbital":
   O-shaped, ambagious, backhanded, circuitous, circular, deviating,
   deviative, devious, digressive, discursive, excursive, helical,
   indirect, meandering, oblique, out-of-the-way, rotary, round,
   roundabout, spiral