The Collaborative International Dictionary of English v.0.48:

Coat \Coat\ (k[=o]t; 110), n. [OF. cote, F. cotte, petticoat,
   cotte d'armes coat of arms, cotte de mailles coat of mail,
   LL. cota, cotta, tunic, prob. of German origin; cf. OHG.
   chozzo coarse mantle, G. klotze, D. kot, hut, E. cot. Cf.
   Cot a hut.]
   1. An outer garment fitting the upper part of the body;
      especially, such a garment worn by men.
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            Let each
            His adamantine coat gird well.        --Milton.
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   2. A petticoat. [Obs.] "A child in coats." --Locke.
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   3. The habit or vesture of an order of men, indicating the
      order or office; cloth.
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            Men of his coat should be minding their prayers.
                                                  --Swift.
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            She was sought by spirits of richest coat. --Shak.
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   4. An external covering like a garment, as fur, skin, wool,
      husk, or bark; as, the horses coats were sleek.
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            Fruit of all kinds, in coat
            Rough or smooth rined, or bearded husk, or shell.
                                                  --Milton.
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   5. A layer of any substance covering another; a cover; a
      tegument; as, the coats of the eye; the coats of an onion;
      a coat of tar or varnish.
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   6. Same as Coat of arms. See below.
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            Hark, countrymen! either renew the fight,
            Or tear the lions out of England's coat. --Shak.
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   7. A coat card. See below. [Obs.]
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            Here's a trick of discarded cards of us! We were
            ranked with coats as long as old master lived.
                                                  --Massinger.
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   Coat armor. See under Armor.

   Coat of arms (Her.), a translation of the French cotte
      d'armes, a garment of light material worn over the armor
      in the 15th and 16th centuries. This was often charged
      with the heraldic bearings of the wearer. Hence, an
      heraldic achievement; the bearings of any person, taken
      together.

   Coat card, a card bearing a coated figure; the king, queen,
      or knave of playing cards. "`I am a coat card indeed.'
      `Then thou must needs be a knave, for thou art neither
      king nor queen.'" --Rowley.

   Coat link, a pair of buttons or studs joined by a link, to
      hold together the lappels of a double-breasted coat; or a
      button with a loop for a single-breasted coat.

   Coat of mail, a defensive garment of chain mail. See Chain
      mail, under Chain.

   Mast coat (Naut.), a piece of canvas nailed around a mast,
      where it passes through the deck, to prevent water from
      getting below.

   Sail coat (Naut.), a canvas cover laced over furled sails,
      and the like, to keep them dry and clean.
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The Collaborative International Dictionary of English v.0.48:

Coat \Coat\ (k[=o]t), v. t. [imp. & p. p. Coated; p. pr. & vb.
   n. Coating.]
   1. To cover with a coat or outer garment.
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   2. To cover with a layer of any substance; as, to coat a jar
      with tin foil; to coat a ceiling.
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WordNet (r) 3.0 (2006):

coat
    n 1: an outer garment that has sleeves and covers the body from
         shoulder down; worn outdoors
    2: a thin layer covering something; "a second coat of paint"
       [syn: coating, coat]
    3: growth of hair or wool or fur covering the body of an animal
       [syn: coat, pelage]
    v 1: put a coat on; cover the surface of; furnish with a
         surface; "coat the cake with chocolate" [syn: coat,
         surface]
    2: cover or provide with a coat
    3: form a coat over; "Dirt had coated her face" [syn: coat,
       cake]

Moby Thesaurus II by Grady Ward, 1.0:

260 Moby Thesaurus words for "coat":
   Eton jacket, Leatherette, Leatheroid, Mao jacket, anorak,
   apply paint, bedaub, bedizen, begild, besmear, blanket, blazer,
   blouse, body coat, bolero, bomber jacket, bonnet, boot, breech,
   bristle, brush on paint, butter, calcimine, cap, capillament,
   capuchin, car coat, chaqueta, chesterfield, chromogen, cilium,
   claw hammer, claw-hammer coat, cloak, coat of paint, coating, coif,
   collop, color, color filter, color gelatin, colorant, coloring,
   complexion, cover, coverage, covering, covert, coverture, cowl,
   cowling, curtain, cut, cutaway coat, cuticle, dab, daub,
   dead-color, deal, deep-dye, dermis, dinner jacket, dip, disk,
   distemper, double-dye, doublet, drape, drapery, dress coat, drier,
   duffel, dye, dyestuff, emblazon, enamel, engild, exterior paint,
   face, facing, fast-dye, fell, feuille, film, fingertip coat,
   fitted coat, flap, flat coat, flat wash, fleece, flesh,
   floor enamel, foil, fold, fresco, frock, frock coat, fur, furring,
   gild, glaze, gloss, gown, grain, greatcoat, ground, guise, hair,
   hanging, hat, hide, hood, horsehair, housing, hue, illuminate,
   imbue, imitation fur, imitation leather, ingrain, integument,
   interior paint, jacket, japan, jerkin, jumper, jupe, lacquer,
   lamella, lamina, laminated glass, laminated wood, lap, lay on,
   lay on color, layer, leaf, leather, leather paper, loden coat,
   mackinaw, mane, mantle, mask, medium, membrane, mess jacket,
   midicoat, monkey jacket, opaque color, outer layer, outer skin,
   overcoat, overlay, paint, pall, pane, panel, parget, parka, patina,
   pea jacket, peel, pellicle, pelt, peltry, pigment, pile, plait,
   plank, plate, plating, ply, plywood, prime, prime coat, primer,
   priming, pubescence, pubic hair, rasher, rawhide, reefer,
   revetment, rind, sack, safety glass, san benito, scale, screen,
   scum, setula, shade, shadow, shag, sheath, sheet, shellac, shelter,
   shield, shirt, shoe, shroud, ski jacket, skin, skins, slab,
   slap on, slat, slather, sleeve waistcoat, slice, slop on paint,
   smear, smear on, smoking jacket, sock, spiketail coat, spread,
   spread on, spread with, stain, stipple, stocking, swallowtail,
   tabard, table, tablet, tail coat, tails, tar, tegument, tempera,
   thinner, tinct, tinction, tincture, tinge, tint, tone, topcoat,
   transparent color, turpentine, turps, undercoat, undercoating,
   vair, varnish, vehicle, veil, veneer, vestment, wafer, wash,
   wash coat, watch coat, whitewash, windbreaker, wool, woolly



Easton's 1897 Bible Dictionary:

Coat
   the tunic worn like the shirt next the skin (Lev. 16:4; Cant.
   5:3; 2 Sam. 15:32; Ex. 28:4; 29:5). The "coats of skins"
   prepared by God for Adam and Eve were probably nothing more than
   aprons (Gen. 3:21). This tunic was sometimes woven entire
   without a seam (John 19:23); it was also sometimes of "many
   colours" (Gen. 37:3; R.V. marg., "a long garment with sleeves").
   The "fisher's coat" of John 21:7 was obviously an outer garment
   or cloak, as was also the "coat" made by Hannah for Samuel (1
   Sam. 2:19). (See DRESS.)