The Collaborative International Dictionary of English v.0.48:

Adorn \A*dorn"\, v. t. [imp. & p. p. Adorned; p. pr. & vb. n.
   Adorning.] [OE. aournen, anournen, adornen, OF. aorner, fr.
   L. aaornare; ad + ornare to furnish, embellish. See Adore,
   Ornate.]
   To deck or dress with ornaments; to embellish; to set off to
   advantage; to render pleasing or attractive.
   [1913 Webster]

         As a bride adorneth herself with her jewels. --Isa.
                                                  lxi. 10.
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         At church, with meek and unaffected grace,
         His looks adorned the venerable place.   --Goldsmith.
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   Syn: To deck; decorate; embellish; ornament; beautify; grace;
        dignify; exalt; honor.

   Usage: To Adorn, Ornament, Decorate, Embellish. We
          decorate and ornament by putting on some adjunct which
          is attractive or beautiful, and which serves to
          heighten the general effect. Thus, a lady's head-dress
          may be ornament or decorated with flowers or jewelry;
          a hall may be decorated or ornament with carving or
          gilding, with wreaths of flowers, or with hangings.
          Ornament is used in a wider sense than decorate. To
          embellish is to beautify or ornament richly, not so
          much by mere additions or details as by modifying the
          thing itself as a whole. It sometimes means gaudy and
          artificial decoration. We embellish a book with rich
          engravings; a style is embellished with rich and
          beautiful imagery; a shopkeeper embellishes his front
          window to attract attention. Adorn is sometimes
          identical with decorate, as when we say, a lady was
          adorned with jewels. In other cases, it seems to imply
          something more. Thus, we speak of a gallery of
          paintings as adorned with the works of some of the
          great masters, or adorned with noble statuary and
          columns. Here decorated and ornamented would hardly be
          appropriate. There is a value in these works of genius
          beyond mere show and ornament. Adorn may be used of
          what is purely moral; as, a character adorned with
          every Christian grace. Here neither decorate, nor
          ornament, nor embellish is proper.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Adorn \A*dorn"\, n.
   Adornment. [Obs.] --Spenser.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Adorn \A*dorn"\, a.
   Adorned; decorated. [Obs.] --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

adorn
    v 1: make more attractive by adding ornament, colour, etc.;
         "Decorate the room for the party"; "beautify yourself for
         the special day" [syn: decorate, adorn, grace,
         ornament, embellish, beautify]
    2: be beautiful to look at; "Flowers adorned the tables
       everywhere" [syn: deck, adorn, decorate, grace,
       embellish, beautify]
    3: furnish with power or authority; of kings or emperors [syn:
       invest, clothe, adorn]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "adorn":
   array, beautify, become one, bedeck, bedizen, bestow honor upon,
   blazon, color, confer distinction on, convolute, dandify, deck,
   deck out, decorate, dignify, distinguish, dizen, doll up, dress,
   dress up, elaborate, embellish, emblazon, embroider, enhance,
   enrich, fancy up, festoon, fig out, fix up, flourish, furbish,
   garnish, gild, glamorize, grace, gussy up, heighten, honor,
   intensify, involve, load with ornament, ornament, overcharge,
   overlay, overload, paint, prank, prank up, preen, prettify,
   pretty up, primp, primp up, prink, prink up, redecorate, redo,
   refurbish, set off, set out, signalize, smarten, smarten up,
   spruce up, titivate, trick out, trick up, trim, varnish