The Collaborative International Dictionary of English v.0.48:

Coronal \Cor"o*nal\ (k?r"?-nal or, esp. in science, k?-r?"nal;
   277), a. [L. coronalis: cf. F. coronal.]
   1. Of or pertaining to a corona (in any of the senses).
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            The coronal light during the eclipse is faint.
                                                  --Abney.
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   2. Of or pertaining to a king's crown, or coronation.
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            The law and his coronal oath require his undeniable
            assent to what laws the Parliament agree upon.
                                                  --Milton.
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   3. Of or pertaining to the top of the head or skull.
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   4. (Zool.) Of or pertaining to the shell of a sea urchin.
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   Coronal suture (Anat.), a suture extending across the skull
      between the parietal and frontal bones; the
      fronto-parietal suture.
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The Collaborative International Dictionary of English v.0.48:

Coronal \Cor"o*nal\, n.
   1. A crown; wreath; garland. --Spenser.
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   2. The frontal bone, over which the ancients wore their
      coron[ae] or garlands. --Hooper.
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WordNet (r) 3.0 (2006):

coronal
    n 1: flower arrangement consisting of a circular band of foliage
         or flowers for ornamental purposes [syn: wreath,
         garland, coronal, chaplet, lei]