The Collaborative International Dictionary of English v.0.48:

Headdress \Head"dress`\ (h[e^]d"dr[e^]s`), n.
   1. A covering or ornament for the head; a headtire; as,
      chiefs among the plains Indians had elaborate long
      headdresses with many feathers.
      [1913 Webster]

            Among birds the males very often appear in a most
            beautiful headdress, whether it be a crest, a comb,
            a tuft of feathers, or a natural little plume.
                                                  --Addison.
      [1913 Webster]

   2. A manner of dressing the hair or of adorning it, whether
      with or without a veil, ribbons, combs, etc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

headdress
    n 1: clothing for the head [syn: headdress, headgear]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "headdress":
   Afro, cap, chapeau, coif, coiffure, cold wave, conk, coverchief,
   haircut, hairdo, hairstyle, handkerchief, hat, headcloth, headgear,
   headpiece, headtire, headwear, home permanent, kerchief, lid,
   millinery, natural, permanent, permanent wave, process, wave



Easton's 1897 Bible Dictionary:

Head-dress
   Not in common use among the Hebrews. It is first mentioned in
   Ex. 28:40 (A.V., "bonnets;" R.V., "head-tires"). It was used
   especially for purposes of ornament (Job 29:14; Isa. 3:23;
   62:3). The Hebrew word here used, _tsaniph_, properly means a
   turban, folds of linen wound round the head. The Hebrew word
   _peer_, used in Isa. 61:3, there rendered "beauty" (A.V.) and
   "garland" (R.V.), is a head-dress or turban worn by females
   (Isa. 3: 20, "bonnets"), priests (Ex. 39:28), a bridegroom (Isa.
   61:10, "ornament;" R.V., "garland"). Ezek. 16:10 and Jonah 2:5
   are to be understood of the turban wrapped round the head. The
   Hebrew _shebisim_ (Isa. 3:18), in the Authorized Version
   rendered "cauls," and marg. "networks," denotes probably a kind
   of netted head-dress. The "horn" (Heb. keren) mentioned in 1
   Sam. 2:1 is the head-dress called by the Druses of Mount Lebanon
   the tantura.