4 letters:
agin, amin, bean, been, dean, gean, gene, jean, kean, keen, lean, lien, mean, mien, nene, seen, teen, wean

5 letters:
amine, chine, ctene, gamin, glean, green, iodin, irene, jeane, keene, preen, quean, queen, rabin, scene, sheen, skean, skene, steen, treen, tsine, tween

6 letters:
alkene, ammine, athene, baleen, butene, careen, casein, cymene, demean, eileen, eocene, ethene, eugene, greene, helene, indene, janine, jeanne, lateen, levine, marine, maxine, mclean, moline, moreen, murine, orpine, ossein, poteen, puisne, purine, racine, ravine, retene, sabine, saline, sateen, screen, selene, serene, silene, sphene, spleen, sthene, umteen, undine, unseen, xylene

7 letters:
abilene, adenine, alcmene, amylene, aniline, beeline, benzene, between, bogbean, bromine, caffein, canteen, citrine, colleen, convene, corinne, corvine, cuisine, dasheen, diamine, eccrine, epicene, epigene, epstein, etamine, fanzine, feldene, fifteen, glycine, guanine, hellene, helxine, hircine, hyaline, hygiene, isoline, jeanine, kuchean, latrine, leucine, machine, marlene, maureen, mcqueen, miocene, myrsine, na-dene, neurine, obscene, olivine, opaline, pauline, phocine, polyene, pontine, preteen, protein, routine, saltine, sardine, savarin, sistine, sixteen, slovene, soybean, styrene, umpteen, unclean, uridine, vaccine

8 letters:
aberdeen, acrolein, aquiline, atrazine, bubaline, buckbean, butylene, caffeine, calycine, camphene, cancrine, carabine, carotene, copaline, cotquean, curarine, cysteine, dauphine, dopamine, eighteen, eleusine, empyrean, ethylene, figurine, fluorine, foreseen, fourteen, francine, gasolene, gasoline, gelatine, goa bean, goethean, holocene, holstein, hyoscine, hypogene, indigene, isoprene, kathleen, kerosene, ketamine, limacine, limonene, limousin, lycopene, magazine, mazarine, melamine, nazarene, neoprene, nicotine, nineteen, novocain, oncogene, pea bean, pliocene, polygene, pyroxene, retinene, sanidine, sciurine, serotine, shagreen, simazine, solanine, spalpeen, terylene, thiazine, thirteen, trephine, triazine, trichion, vaseline, wax bean, yam bean, yestreen, zigadene, zygotene

9 letters:
acetylene, adenosine, aposelene, argentine, atlantean, augustine, barbotine, bengaline, benzoline, blue jean, bombazine, broadbean, butadiene, byzantine, caesarean, carrageen, chow mein, christine, cinnamene, clonidine, colubrine, crinoline, damascene, dindymene, diplotene, dramamine, dry-clean, evergreen, fava bean, feinstein, fullerene, gabardine, geraldine, goldstein, grenadine, guanidine, guanosine, halloween, histamine, histidine, holocrine, horsebean, hydrazine, inquiline, intervene, jack bean, josephine, leptotene, libertine, lima bean, limousine, madrilene, magdalene, may queen, melpomene, mescaline, metformin, methylene, mezzanine, misdemean, monoamine, moth bean, mujahedin, naphthene, navy bean, nectarine, nyctimene, oligocene, organzine, ornithine, pachytene, palanquin, paleocene, pea green, percaline, peregrine, phosphene, phosphine, photogene, prolamine, propylene, protamine, quinidine, reconvene, rhodamine, safranine, sea-green, sea green, seventeen, snap bean, soja bean, soya bean, spodumene, stanchion, submarine, sunscreen, supervene, tambourin, tangerine, terrapene, thiophene, thorazine, thylacine, thymidine, toxaphene, transgene, velveteen, veratrine, vulturine, weinstein, wild bean, wolf bean, wolverine

10 letters:
anthracene, aquamarine, asparagine, azobenzene, beet green, black bean, broad bean, butterbean, by machine, carob bean, carragheen, catarrhine, cimetidine, civet bean, clementine, clomiphene, cocoa bean, contravene, coral bean, dark-green, delawarean, didanosine, ergotamine, ethylamine, fescennine, field bean, florentine, fresh bean, gentamicin, ghibelline, glyoxaline, go-between, green bean, guillotine, hallowe'en, horse bean, houseclean, in-between, isoleucine, jade-green, jade green, jelly bean, lacustrine, mangosteen, margravine, merbromine, mesitylene, mondegreen, moss green, mujahideen, nalorphine, oxybenzene, palustrine, paraselene, periselene, philippine, philistine, pinto bean, piperazine, plasticine, promethean, pseudogene, pyrimidine, quarantine, rosaniline, sage-green, sage green, sapphirine, screw bean, shell bean, silkscreen, snail bean, subroutine, sword bean, tambourine, tartrazine, terreplein, tonka bean, tourmaline, trampoline, tyrocidine, unforeseen, white bean, widescreen, windscreen

11 letters:
accipitrine, acriflavine, amaranthine, amphetamine, bengal bean, benzopyrene, butter bean, castor bean, chloroprene, coffee bean, common bean, constantine, cress green, cycloserine, edible bean, elephantine, epinephrine, fetoprotein, fire screen, floxuridine, french bean, glucosamine, golden mean, hammerstein, hyacinthine, hydralazine, hyoscyamine, hypersthene, ice machine, incarnadine, indian bean, internecine, iodoprotein, isobutylene, jean racine, kidney bean, leukotriene, light-green, locust bean, mandelamine, manila bean, methenamine, methylamine, mucoprotein, naphthalene, nitrosamine, olive green, ordeal bean, paris green, pentamidine, pentazocine, phenylamine, philhellene, pleistocene, polystyrene, potato bean, rood screen, runner bean, salad green, scopolamine, silk-screen, smokescreen, springsteen, string bean, tendergreen, theobromine, thioguanine, transferrin, transmarine, turtle bean, velvet bean, wide screen, winged bean, wintergreen, wonder bean, yellow bean, zalcitabine

12 letters:
arsphenamine, bluish green, bottle green, cash machine, chrome green, closet queen, cluster bean, coin machine, cyclosporine, dump routine, english bean, ethanolamine, farm machine, flavoprotein, florida bean, fluphenazine, frankenstein, genus selene, glycoprotein, hangar queen, homocysteine, hypoxanthine, jumping bean, kendal green, labyrinthine, lactoprotein, on-the-scene, oxyacetylene, perphenazine, phenanthrene, phentolamine, polybutylene, polyethylene, procarbazine, promethazine, propoxyphene, pyridoxamine, salk vaccine, slot machine, smoke screen, spring-clean, sulfadiazine, tape machine, thioridazine, thyroprotein, time machine, transpontine, tubocurarine, vacuum-clean, vanilla bean, vinylbenzene, yellow green

13 letters:
antisubmarine, beta-carotene, bowling green, catecholamine, cephaloridine, chlorobenzene, diphenylamine, egyptian bean, european bean, field soybean, genus glycine, golden spleen, green soybean, harmonic mean, hyacinth bean, hydroxylamine, input routine, methapyrilene, methylbenzene, nucleoprotein, penicillamine, phenothiazine, phenylalanine, phenylephrine, polypropylene, pulp magazine, putting green, pyrimethamine, rhadamanthine, sabin vaccine, scleroprotein, silver screen, telex machine, the argentine, village green, windsor green, x-ray machine, xerox machine

14 letters:
adding machine, asparagus bean, azidothymidine, chlorpromazine, geometric mean, hooker's green, hydroxybenzene, mary magdalene, mental hygiene, mercaptopurine, mobile canteen, norepinephrine, output routine, paving machine, phenylethylene, phosphoprotein, proto-oncogene, sawing machine, sewing machine, silver protein, simple machine, simple protein, slick magazine, sulfamethazine, sulfamezathine, voting machine

15 letters:
arithmetic mean, bathing machine, christmas green, computer screen, dandelion green, hexachloraphene, hexachlorophene, library routine, mephistophelean, merchant marine, milking machine, milling machine, mincing machine, pacific sardine, phosphocreatine, pinball machine, powder magazine, saint augustine, service routine, textile machine, tracing routine, utility routine, vending machine, washing machine, when first seen, yellowish green

16 letters:
attack submarine, chryselephantine, compound protein, dialysis machine, diffusing screen, franking machine, giant stock bean, infernal machine, knitting machine, printing machine, prochlorperazine, reusable routine, riveting machine, spinning machine, stapling machine, teletype machine, weighing machine

17 letters:
alpha-fetoprotein, chinese evergreen, dextroamphetamine, diathermy machine, executive routine, facsimile machine, perchloroethylene, political machine, projection screen, recording machine, ribonucleoprotein, thiodiphenylamine, trichloroethylene

18 letters:
addressing machine, conjugated protein, lithograph machine, mimeograph machine

19 letters:
calculating machine, dishwashing machine, english runner bean, mild silver protein, phenylpropanolamine, scarlet runner bean, supervisory routine, tetrachloroethylene, tetrafluoroethylene, typesetting machine, von neumann machine

20 letters:
active matrix screen, kentucky wonder bean, mexican jumping bean

21 letters:
electrostatic machine

22 letters:
dihydroxyphenylalanine

23 letters:
polytetrafluoroethylene

24 letters:
automated teller machine, automatic teller machine

26 letters:
regression toward the mean

27 letters:
microwave diathermy machine, shortwave diathermy machine

28 letters:
auxiliary research submarine, mean deviation from the mean

29 letters:
methylenedioxymethamphetamine

33 letters:
fleet ballistic missile submarine