1 letter:
.

3 letters:
boa, egg, gel, icy, lag, pad, rod, soy, tin

4 letters:
bony, card, chip, clad, coat, cuke, cusp, film, fine, flap, foil, iris, kine, lank, lath, lead, line, mica, mist, nail, peel, pick, reed, safe, shim, skim, skin, slat, stay, tapa, tape, tile, trim, wash, waxy, weak

5 letters:
acorn, arrow, atole, bacon, baton, birch, blade, broth, capiz, chaff, crape, crepe, crisp, filmy, flake, flash, gaunt, gauzy, glaze, gleet, grout, gruel, knife, lanky, layer, lichi, light, lymph, match, mylar, pizza, plate, rangy, scale, scaly, scurf, sharp, sheer, sheet, slate, slice, smear, spall, spare, spawl, stave, stick, straw, strip, tappa, thick, thong, tinny, toffy, tower, virus, vomer, wafer, washy, waste, wispy

6 letters:
alpaca, amnion, amnios, batter, beaten, bladed, blintz, canape, carbon, column, condom, cutlet, disbud, finger, flimsy, folium, gangly, lamina, latten, leaded, lichee, litchi, lychee, manila, papery, paring, pencil, phyllo, pillar, piping, platan, pleura, pongee, ribbon, rubber, safety, scaled, scaley, schist, serosa, skilly, sleazy, sliver, spline, splint, thread, tissue, toffee, tongue, toucan, veneer, wasted, watery, webbed

7 letters:
air sac, baklava, balloon, batiste, blintze, brittle, chiffon, coating, contact, cracker, eellike, fimbria, foliate, gelatin, haggard, hoecake, hotcake, kleenex, kumquat, lamella, leading, leaflet, leechee, litchee, lucifer, manilla, oarfish, oatcake, palmate, pancake, pinched, plating, plywood, ribbony, satsuma, scallop, scalpel, scollop, scumble, section, shaving, shellac, slating, spatula, steamer, strudel, tabasco, tenuous, thready, tinning, unlined, unwoven

8 letters:
anodonta, anorexic, calender, catheter, cobwebby, crossbar, crustose, cucumber, dressing, emaciate, ependyma, escallop, filament, filiform, fineness, flapcake, flapjack, flatbrod, flatfish, flinders, foliated, gangling, gossamer, hairline, hot cake, julienne, laminate, macerate, magnetic, mag tape, mandarin, membrane, napoleon, obsidian, peduncle, peel off, pellicle, plectron, plectrum, plyboard, skeletal, slimness, snow pea, splinter, sprocket, stingray, sukiyaki, sunchoke, sycamore, synovium, thinness, thin air, thin out, tortilla, ulvaceae, vaporous, wisplike

9 letters:
anorectic, aquaplane, arteriola, arteriole, bitternut, black ice, book lung, cell wall, chipolata, clapboard, clingfilm, cloisonne, corn chip, crookneck, cytosmear, dasymeter, dermatome, dreadlock, ductility, ectomorph, emaciated, excelsior, exfoliate, flake off, flakiness, foliation, georgette, gold leaf, gooseneck, grenadine, hyperfine, isinglass, jackstraw, jellyroll, lankiness, microtome, nakedwood, net melon, oil slick, onionskin, paillasse, palliasse, pemphigus, pepperoni, pizza pie, prosciuto, razorback, root hair, scrub oak, soy sauce, spade bit, spillikin, sugar pea, tin plate, veneering, vermiform, wallboard, wish-wash

10 letters:
adsorption, battercake, birch tree, cadaverous, christella, cling film, coping saw, diaphanous, flat solid, foliaceous, gold plate, harvestman, kuri-chiku, lamination, litchi nut, lubricious, matchstick, neurilemma, neurolemma, paper thin, parenchyma, piano wire, pinstripea, pinstriped, plane tree, plethodont, pleximeter, pycnogonid, razor clam, red pepper, ribbonfish, ribbonlike, rice paper, saran wrap, scallopine, scallopini, sea spider, sea urchin, slightness, soundboard, swiss roll, threadlike, titanosaur, wafer-thin, water down, windowpane

11 letters:
appallingly, bottlebrush, compass saw, endothelium, exfoliation, featheredge, feather boa, filamentous, glass fiber, glass fibre, griddlecake, india paper, indignantly, lantern jaw, letter bomb, melba toast, parcel bomb, phragmacone, phragmocone, plastic bag, plate glass, plessimeter, potato chip, scarlet cup, see-through, shapelessly, sheet glass, sheet metal, slenderness, slumgullion, soap bubble, spaghettini, spindlelegs, thin person, ticker tape, transparent, wild carrot, worm-shaped

12 letters:
amniotic sac, black bamboo, brittle fern, bubble shell, canaliculate, carbon paper, cirrostratus, contact lens, cytomembrane, electroplate, filamentlike, flannel-cake, flannel cake, fragile fern, knife-handle, longitudinal, manila paper, minute steak, mya arenaria, netted melon, nutmeg melon, package bomb, plastic film, plastic wrap, prophylactic, roofing tile, scarecrowish, silver plate, sitka spruce, spectrometer, steamer clam, sweet orange, t-bone steak, tissue paper, toilet paper, weatherboard, yellow birch

13 letters:
betula leutea, bitter pignut, cell membrane, common bamboo, daucus carota, firmer chisel, magnetic tape, manilla paper, metal plating, optical fiber, optical fibre, oversensitive, rat-tail file, razorback hog, saddle oyster, saratoga chip, smooth muscle, spindleshanks, swamp hickory, titanosaurian, toilet tissue, water biscuit, whip-scorpion, whip scorpion, window oyster, wood shavings, writing paper

14 letters:
bitter hickory, crepe de chine, daddy longlegs, drinking straw, english walnut, folsom culture, fortune cookie, french pancake, friction match, genus anodonta, iris diaphragm, jackknife clam, long-neck clam, quartz crystal, salad dressing, shrink-wrapped, skin and bones, sounding board, sprocket wheel, vibrating reed

15 letters:
annular eclipse, bathroom tissue, cytologic smear, eugenia dicrana, family ulvaceae, italian cypress, mandarin orange, out of thin air, pars intermedia, plasma membrane, razorbacked hog, serous membrane, shellac varnish, soft-shell clam, torsion balance, veal scallopini, weatherboarding

16 letters:
anomia ephippium, bambusa vulgaris, bowman's capsule, butternut squash, capillary artery, crookneck squash, crustose thallus, cucurbita maxima, euonymous alatus, lath and plaster, picea sitchensis, placuna placenta, regalecus glesne, summer crookneck, tongue depressor, veal cordon bleu

17 letters:
bitternut hickory, capsula glomeruli, carya cordiformis, citrus reticulata, hairline fracture, mass spectrometer, needlenose pliers, phalangium opilio, queen anne's lace, quilted bedspread, synovial membrane, windowpane oyster

18 letters:
capillary fracture, cirrostratus cloud, glomerular capsule, sea-lettuce family, suricata suricatta

19 letters:
calostoma ravenelii, chicken cordon bleu, jerusalem artichoke, king of the herring, lungless salamander, mercury thermometer, phyllostachys nigra, thin-shelled mussel, winged spindle tree

20 letters:
brittle bladder fern, cystopteris fragilis, gastrocybe lateritia, mandarin orange tree, sarcoscypha coccinea, scophthalmus aquosus, surface assimilation

21 letters:
betula alleghaniensis, mediterranean cypress, necrobiosis lipoidica

22 letters:
cupressus sempervirens, lamellate placentation, magnetic bubble memory, slender-tailed meerkat

24 letters:
cucumis melo reticulatus

27 letters:
serratus posterior inferior, serratus posterior superior

28 letters:
mercury-in-glass thermometer

34 letters:
necrobiosis lipoidica diabeticorum