The Collaborative International Dictionary of English v.0.48:

Parietal \Pa*ri"e*tal\, a. [L. parietalis, fr. paries, -ietis, a
   wall: cf. F. pari['e]tal. Cf. Parietary, Pellitory.]
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   1. Of or pertaining to a wall; hence, pertaining to buildings
      or the care of them.
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   2. Resident within the walls or buildings of a college.
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            At Harvard College, the officers resident within the
            college walls constitute a permanent standing
            committee, called the Parietal Committee. --B. H.
                                                  Hall (1856).
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   3. (Anat.)
      (a) Of or pertaining to the parietes.
      (b) Of, pertaining to, or in the region of, the parietal
          bones, which form the upper and middle part of the
          cranium, between the frontals and occipitals.
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   4. (Bot.) Attached to the main wall of the ovary, and not to
      the axis; -- said of a placenta.
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The Collaborative International Dictionary of English v.0.48:

Parietal \Pa*ri"e*tal\, n.
   1. (Anat.) One of the parietal bones.
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   2. (Zool.) One of the special scales, or plates, covering the
      back of the head in certain reptiles and fishes.
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WordNet (r) 3.0 (2006):

parietal
    adj 1: of or relating to or associated with the parietal bones
           in the cranium; "parietal lobe"