The Collaborative International Dictionary of English v.0.48:

Scan \Scan\ (sk[a^]n), v. t. [imp. & p. p. Scanned (sk[a^]nd);
   p. pr. & vb. n. Scanning.] [L. scandere, scansum, to climb,
   to scan, akin to Skr. skand to spring, leap: cf. F. scander.
   Cf. Ascend, Descend, Scale a ladder.]
   1. To mount by steps; to go through with step by step. [Obs.]
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            Nor stayed till she the highest stage had scand.
                                                  --Spenser.
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   2. Specifically (Pros.), to go through with, as a verse,
      marking and distinguishing the feet of which it is
      composed; to show, in reading, the metrical structure of;
      to recite metrically.
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   3. To go over and examine point by point; to examine with
      care; to look closely at or into; to scrutinize.
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            The actions of men in high stations are all
            conspicuous, and liable to be scanned and sifted.
                                                  --Atterbury.
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   4. To examine quickly, from point to point, in search of
      something specific; as, to scan an article for mention of
      a particular person.
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   5. (Electronics) To form an image or an electronic
      representation of, by passing a beam of light or electrons
      over, and detecting and recording the reflected or
      transmitted signal.
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