The Collaborative International Dictionary of English v.0.48:

Drier \Dri"er\, n.
   1. One who, or that which, dries; that which may expel or
      absorb moisture; a desiccative; as, the sun and a
      northwesterly wind are great driers of the earth.
      [1913 Webster]

   2. (Paint.) Drying oil; a substance mingled with the oil used
      in oil painting to make it dry quickly. Drier

The Collaborative International Dictionary of English v.0.48:

Drier \Dri"er\, compar., Driest \Dri"est\, superl.,
   of Dry, a.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dry \Dry\ (dr[imac]), a. [Compar. Drier; superl. Driest.]
   [OE. dru[yogh]e, druye, drie, AS. dryge; akin to LG.
   dr["o]ge, D. droog, OHG. trucchan, G. trocken, Icel. draugr a
   dry log. Cf. Drought, Drouth, 3d Drug.]
   1. Free from moisture; having little humidity or none; arid;
      not wet or moist; deficient in the natural or normal
      supply of moisture, as rain or fluid of any kind; -- said
      especially:
      (a) Of the weather: Free from rain or mist.
          [1913 Webster]

                The weather, we agreed, was too dry for the
                season.                           --Addison.
      (b) Of vegetable matter: Free from juices or sap; not
          succulent; not green; as, dry wood or hay.
      (c) Of animals: Not giving milk; as, the cow is dry.
      (d) Of persons: Thirsty; needing drink.
          [1913 Webster]

                Give the dry fool drink.          -- Shak
      (e) Of the eyes: Not shedding tears.
          [1913 Webster]

                Not a dry eye was to be seen in the assembly. --
                                                  Prescott.
      (f) (Med.) Of certain morbid conditions, in which there is
          entire or comparative absence of moisture; as, dry
          gangrene; dry catarrh.
          [1913 Webster]

   2. Destitute of that which interests or amuses; barren;
      unembellished; jejune; plain.
      [1913 Webster]

            These epistles will become less dry, more
            susceptible of ornament.              --Pope.
      [1913 Webster]

   3. Characterized by a quality somewhat severe, grave, or
      hard; hence, sharp; keen; shrewd; quaint; as, a dry tone
      or manner; dry wit.
      [1913 Webster]

            He was rather a dry, shrewd kind of body. --W.
                                                  Irving.
      [1913 Webster]

   4. (Fine Arts) Exhibiting a sharp, frigid preciseness of
      execution, or the want of a delicate contour in form, and
      of easy transition in coloring.
      [1913 Webster]

   Dry area (Arch.), a small open space reserved outside the
      foundation of a building to guard it from damp.

   Dry blow.
      (a) (Med.) A blow which inflicts no wound, and causes no
          effusion of blood.
      (b) A quick, sharp blow.

   Dry bone (Min.), Smithsonite, or carbonate of zinc; -- a
      miner's term.

   Dry castor (Zool.) a kind of beaver; -- called also
      parchment beaver.

   Dry cupping. (Med.) See under Cupping.

   Dry dock. See under Dock.

   Dry fat. See Dry vat (below).

   Dry light, pure unobstructed light; hence, a clear,
      impartial view. --Bacon.
      [1913 Webster]

            The scientific man must keep his feelings under
            stern control, lest they obtrude into his
            researches, and color the dry light in which alone
            science desires to see its objects.   -- J. C.
                                                  Shairp.

   Dry masonry. See Masonry.

   Dry measure, a system of measures of volume for dry or
      coarse articles, by the bushel, peck, etc.

   Dry pile (Physics), a form of the Voltaic pile, constructed
      without the use of a liquid, affording a feeble current,
      and chiefly useful in the construction of electroscopes of
      great delicacy; -- called also Zamboni's, from the names
      of the two earliest constructors of it.

   Dry pipe (Steam Engine), a pipe which conducts dry steam
      from a boiler.

   Dry plate (Photog.), a glass plate having a dry coating
      sensitive to light, upon which photographic negatives or
      pictures can be made, without moistening.

   Dry-plate process, the process of photographing with dry
      plates.

   Dry point. (Fine Arts)
      (a) An engraving made with the needle instead of the
          burin, in which the work is done nearly as in etching,
          but is finished without the use acid.
      (b) A print from such an engraving, usually upon paper.
      (c) Hence: The needle with which such an engraving is
          made.

   Dry rent (Eng. Law), a rent reserved by deed, without a
      clause of distress. --Bouvier.

   Dry rot, a decay of timber, reducing its fibers to the
      condition of a dry powdery dust, often accompanied by the
      presence of a peculiar fungus (Merulius lacrymans),
      which is sometimes considered the cause of the decay; but
      it is more probable that the real cause is the
      decomposition of the wood itself. --D. C. Eaton. Called
      also sap rot, and, in the United States, powder post.
      --Hebert.

   Dry stove, a hothouse adapted to preserving the plants of
      arid climates. --Brande & C.

   Dry vat, a vat, basket, or other receptacle for dry
      articles.

   Dry wine, that in which the saccharine matter and
      fermentation were so exactly balanced, that they have
      wholly neutralized each other, and no sweetness is
      perceptible; -- opposed to sweet wine, in which the
      saccharine matter is in excess.
      [1913 Webster]

WordNet (r) 3.0 (2006):

drier
    n 1: a substance that promotes drying (e.g., calcium oxide
         absorbs water and is used to remove moisture) [syn:
         desiccant, drying agent, drier, siccative]
    2: an appliance that removes moisture [syn: dryer, drier]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "drier":
   air brush, art paper, brush, camera lucida, camera obscura, canvas,
   chalk, charcoal, chromogen, clothes-drier, coat, coat of paint,
   coating, color, color filter, color gelatin, colorant, coloring,
   crayon, dead-color, dehumidifier, dehydrant, dehydrator,
   desiccative, desiccator, distemper, drawing paper, drawing pencil,
   dye, dyestuff, easel, evaporator, exsiccative, exsiccator,
   exterior paint, fixative, flat coat, flat wash, floor enamel,
   ground, interior paint, lay figure, maulstick, medium,
   opaque color, paint, paintbrush, palette, palette knife, pastel,
   pencil, pigment, pigments, prime coat, primer, priming,
   scratchboard, siccative, sketchbook, sketchpad, spatula, spray gun,
   stain, stump, tempera, thinner, tinction, tincture,
   transparent color, turpentine, turps, undercoat, undercoating,
   varnish, vehicle, wash, wash coat