3 letters:
ear, kir, mir

4 letters:
amir, beer, bere, bier, dear, deer, emir, fear, gear, gere, hear, here, jeer, kier, lear, meir, mere, near, neer, peer, pier, rear, sear, seer, sere, tear, tier, veer, weir, wier, year

5 letters:
ashir, astir, blear, cheer, clear, drear, fleer, greer, grier, peart, queer, sapir, shear, sheer, smear, sneer, spear, speer, steer, vanir, we're, yasir, zaire

6 letters:
adhere, appear, arrear, career, coheir, cohere, diapir, endear, fakeer, inhere, kaffir, lanier, menhir, rehear, revere, severe, shamir, shmear, sphere, uprear, veneer

7 letters:
austere, besmear, cashier, compeer, compere, dog-ear, guinier, houhere, kildeer, mishear, mynheer, pioneer, premier, rainier, schmear, sea-ear, sincere, tangier, tarsier, unclear, up here

8 letters:
abampere, cavalier, domineer, engineer, footgear, frontier, give ear, isothere, killdeer, lavalier, low gear, muleteer, mutineer, overhear, per year, premiere, reappear, red deer, roe deer, souvenir, sun gear, wheatear

9 letters:
adipocere, all clear, balladeer, bandoleer, bandolier, basketeer, belvedere, bock beer, brigadier, buccaneer, cannoneer, carbineer, chevalier, come near, dark beer, disappear, draw near, each year, financier, gadgeteer, gazetteer, gondolier, guinevere, held dear, high gear, hold dear, holy year, indinavir, inner ear, insincere, interfere, leap year, life peer, megathere, micromere, mouse-ear, mouse ear, mule deer, musketeer, musk deer, near beer, outer ear, oversteer, over here, pap smear, persevere, pistoleer, presbyter, privateer, profiteer, puppeteer, racketeer, root beer, sightseer, sloganeer, sonneteer, spur gear, trochlear, volunteer, wasteweir, worm gear

10 letters:
auctioneer, bear's ear, bevel gear, birch beer, bombardier, burro deer, carabineer, chandelier, charioteer, civil year, commandeer, every year, first gear, gondoliere, great year, halberdier, harpooneer, in one ear, light beer, light year, lunar year, middle ear, mouse deer, nelfinavir, saquinavir, scrutineer, small beer, solar year, third gear, to one ear, uintathere, understeer, water deer, weiss beer

11 letters:
bronx cheer, chanticleer, church year, common year, edward lear, electioneer, electrolier, fallow deer, fiscal year, ginger beer, hydrometeor, microampere, milliampere, montgolfier, munich beer, pamphleteer, planet gear, schenk beer, school year, second gear, shakespeare, spruce beer, stable gear, volt-ampere

12 letters:
barking deer, bartle frere, elephant ear, external ear, far and near, fishing gear, internal ear, king's spear, landing gear, peer-to-peer, time of year, without fear

13 letters:
academic year, army engineer, calendar year, conventioneer, crystal clear, japanese deer, last frontier, platonic year, porte-cochere, porter's beer, steering gear, tropical year, virginia deer

14 letters:
cervical smear, christian year, civil engineer, elephant's ear, financial year, naval engineer, planetary gear, whitetail deer, world premiere

15 letters:
black marketeer, cauliflower ear, flight engineer, jewish new year, kilovolt-ampere, marine engineer, mining engineer, sabbatical year

16 letters:
capital of zaire, celestial sphere, highway engineer, political sphere

17 letters:
astronomical year, differential gear, military engineer, pere david's deer, railroad engineer, software engineer

18 letters:
aerospace engineer, military volunteer

19 letters:
automotive engineer, efficiency engineer, elasticity of shear, electrical engineer, mechanical engineer, william shakespeare

20 letters:
pinion and ring gear, vestibule of the ear

21 letters:
aeronautical engineer

22 letters:
metallurgical engineer

1 letter:
r

2 letters:
ar, or, er, r.

3 letters:
bur, for, jar, npr, air, par, fur, mar, war, err, far, oar, ore, gar, car, ayr, tor, sir, are, ire, cur, nor, bar, tar, per, fir

4 letters:
bear, pare, lore, more, sour, slur, dare, poor, lour, gore, torr, door, wear, bore, fair, tyre, dire, boer, were, spar, hire, boar, hare, core, hour, star, lair, boor, sore, sure, mare, yore, pair, wore, pore, soar, moor, hair, cure, fare, four, herr, doer, fore, carr, scar, your, parr, care, burr, fire, czar, wire, pour, rare, dour, bare, tsar, blur, birr, lyre, tore, ware, mire, char, spur, pure, ruhr, hoar, lure, thor, purr, heir, pear, stir, tour, roar, barr, adar, abor, fahr, fehr, igor, jour, lohr, voir

5 letters:
khmer, score, loire, aware, blair, moore, assur, barre, whore, crore, churr, snore, skier, glare, blare, sitar, ne'er, qatar, flair, chore, scour, defer, flare, afire, store, amour, spore, dower, senor, demur, safar, corps, share, shirr, babar, stair, unbar, there, snare, chirr, stare, inure, shore, floor, myrrh, their, inter, quire, swear, adore, spare, dakar, abhor, incur, shire, dinar, bazar, chair, flour, spoor, occur, refer, scare, starr, moire, infer, deter, spire, decor, murre, swore, recur, where, cigar, asarh, athar, bihar, damar, debar, freyr, kotar, lamar, maher, selar, sherr, vidar, whirr

6 letters:
lekvar, unfair, impure, secure, velour, impair, insure, guitar, drawer, confer, midair, ensure, affair, assure, square, immure, bazaar, aspire, adjure, galore, so far, pierre, vigour, disbar, unsure, endure, ignore, squire, retire, beware, concur, repair, prayer, tumour, valour, claire, prewar, detour, mature, go for, before, qintar, poseur, ashore, vapour, prefer, manure, you're, demure, savour, voyeur, allure, admire, by far, expire, abjure, aflare, anshar, bonior, cottar, devoir, eclair, exmoor, go far, isobar, jamjar, lenore, lontar, nuphar, o'hare, pindar, rigour, safire, salvor, sambar, sambur, schorr, secpar

7 letters:
ask for, verdure, hot air, big sur, myanmar, respire, rapport, pasteur, hot war, pay for, compare, inshore, liqueur, anymore, prepare, require, deplore, they're, inquire, postwar, saviour, masseur, inspire, restore, bizarre, couture, ensnare, declare, au pair, danseur, succour, de jure, obscure, unaware, fervour, procure, explore, flavour, affaire, despair, wet bar, implore, astaire, bonaire, bonheur, bugbear, co-star, cooccur, cry for, flexure, forbear, gravure, hachure, languor, minibar, moliere, nervure, not far, no more, nut bar, on tour, opt for, outroar, pry bar, rancour, run for, samovar, shophar, soilure, tonsure, try for, tussore, tv star, upstair, vitharr, wafture, who are, you are

8 letters:
brochure, grimoire, look for, call for, nightjar, sea star, polypore, brumaire, send for, reinsure, boer war, milk bar, seigneur, what for, tank car, offshore, due care, saboteur, day care, wood tar, frotteur, dog star, lead ore, ant bear, grandeur, immature, fall for, pace car, frimaire, bell jar, open air, voltaire, monsieur, care for, sea hare, coal tar, reassure, for sure, debonair, forswear, cash bar, perspire, done for, pine tar, transfer, sand bar, cold war, a. t. r., abattoir, allosaur, amanpour, axle bar, baccilar, barosaur, blue air, bog star, bus fare, c. p. r., cab fare, calm air, car care, car door, cat bear, coal car, coiffeur, coiffure, coinsure, date bar, derriere, elaphure, encolure, ex-mayor, f. d. r., feel for, fend for, footsure, gill bar, got your, grab bar, handwear, high bar, hot-wire, ice bear, iron ore, longueur, mail car, make for, markhoor, microbar, open-air, outscore, overbear, p. c. r., paramour, parterre, peignoir, put your, r. j. r., race car, scimitar, sinecure, slop jar, t-square, take for, tamanoir, testiere, thus far, true fir, twoscore, v. c. r., voussoir, what are, wirehair

9 letters:
guarantor, blue star, rock star, fire door, candy bar, light air, stock car, superstar, great war, price war, snack bar, raconteur, speak for, joint fir, solitaire, squad car, trap door, back door, salad bar, premature, root hair, world war, civil war, color bar, disrepair, pinch bar, cold sore, barn door, space bar, stand for, cable car, take care, chauffeur, au revoir, skin care, film star, make sure, wild boar, mason jar, open door, next door, air corps, allow for, apatosaur, archosaur, cabin car, cafe noir, cared-for, carob bar, chair car, chinaware, class war, coon bear, cover for, debonaire, downstair, duty tour, fourscore, fruit bar, giant fir, give care, go to war, grand fir, grope for, gum myrrh, hadrosaur, hair care, half door, hekmatyar, hoped-for, horsehair, in so far, kala-azar, make pure, metal bar, nothosaur, once more, plump for, plunk for, prowl car, pterosaur, pushchair, quest for, red scare, rest-cure, scout car, set afire, shoot for, side door, slice bar, sorry for, sport car, stall bar, stegosaur, stud mare, sushi bar, sweep oar, taxi fare, that your, there are, towel bar, warrantor, where are, white fir

10 letters:
quadrature, answer for, great bear, buffet car, polar star, pinot noir, flare star, honey bear, cookie jar, racing car, try square, bumper car, double bar, korean war, liquid air, leyden jar, tidal bore, bath chair, north star, escritoire, front door, louis d'or, lawn chair, black bear, pubic hair, dutch door, in the air, mal de mer, set square, dining car, polar bear, deck chair, side chair, foursquare, underscore, balsam fir, sports car, heavy spar, child care, heretofore, swing door, shop floor, trojan war, easy chair, petit four, movie star, patrol car, guard hair, brown bear, giant star, silver fir, police car, stage door, fixed star, grand tour, estate car, wing chair, teddy bear, koala bear, parlor car, air-to-air, alpine fir, ankylosaur, baudelaire, belshazzar, blackamoor, brontosaur, budget for, called for, camp chair, cattle car, ceratosaur, cockleburr, coffee bar, cross hair, debonnaire, embouchure, faith cure, false hair, fraser fir, god of war, great care, ground fir, ictodosaur, jaunty car, kieselguhr, longed-for, looked-for, man-of-war, marsh hare, mens store, mouse hare, opera star, oregon fir, oyster bar, palace car, panda bear, peanut bar, pelycosaur, plesiosaur, polar hare, re-explore, river pear, scotch fir, secretaire, seismosaur, set ashore, shoe store, skunk bear, sloth bear, smoothbore, swamp hare, texas star, threescore, to be sure, track star, train fare, tug-of-war, wished-for, woody pear

11 letters:
freight car, baggage car, saddle sore, apgar score, word square, binary star, kodiak bear, trolley car, crimean war, uncared-for, gondola car, billionaire, woolly bear, litterateur, doctrinaire, dental care, first floor, dance floor, sedan chair, millionaire, little bear, solar flare, connoisseur, candy store, love affair, silver star, peace corps, bronze star, arctic char, limited war, screen door, ichthyosaur, account for, health care, vanity fair, douglas fir, balsam pear, mexican war, potty chair, basket star, double star, vietnam war, french door, flying mare, six day war, touring car, apricot bar, arctic hare, beach chair, black maire, buffalo bur, camera care, candidature, come before, come in for, compact car, corythosaur, cry out for, death chair, double door, dressed ore, dromaeosaur, dyaus-pitar, gala affair, golden star, gomphothere, granola bar, hershey bar, iraqi dinar, liquidambar, looking for, lowland fir, mineral tar, native bear, native pear, ocean floor, parlour car, peacock ore, prepare for, press corps, provide for, puff of air, pullman car, railway car, ripping bar, rotogravure, seckel pear, slight care, smoking car, spanish war, squeeze for, styracosaur, subway fare, supersedure, syrian bear, take a dare, that you're, tyrannosaur, ulaanbaatar, unhoped-for, uranium ore, walk on air, what's your, what you're, white maire, wicket door, yacht chair, yearned-for

12 letters:
morris chair, evening star, sleeping car, bill of fare, morning star, blazing star, wrecking bar, camel's hair, ground floor, magic square, folding door, feather star, state of war, grizzly bear, iceland spar, entrepreneur, belgian hare, times square, white squire, bevel square, neutron star, prickly pear, sloop of war, steel guitar, brittle star, kuala lumpur, marine corps, liquor store, anchovy pear, swivel chair, avocado pear, green manure, latin square, restaurateur, soup du jour, aide-memoire, barber chair, buffer store, ceramic ware, colorado fir, electric car, elevator car, flower store, garden chair, going ashore, head of hair, heliogravure, hitching bar, in disrepair, leisure wear, libyan dinar, lounge chair, marston moor, medical care, nursing care, outside door, photogravure, pied-a-terre, powder store, prairie star, psittacosaur, railroad car, retail store, savoir-faire, sensory hair, serpent star, service door, sliding door, standing for, staurikosaur, that you are, uncalled-for, unlooked-for, unwished-for, varying hare, vina del mar, what is more, yemeni dinar

13 letters:
nom de guerre, lord's prayer, wear and tear, laissez faire, multiple star, snowshoe hare, louis pasteur, questionnaire, haute couture, passenger car, rocking chair, general store, cinnamon bear, package store, force majeure, rouge et noir, variable star, shooting star, windsor chair, grocery store, and there are, bahrain dinar, bartlett pear, bowling score, bring to bear, carte du jour, chocolate bar, conservatoire, cote d'ivoire, country store, devil's cigar, european hare, exterior door, feeding chair, folding chair, hospital care, interior door, iranian dinar, jewelry store, kangaroo bear, kangaroo hare, kuwaiti dinar, laissez-faire, market square, more and more, musical score, operatic star, ordinary care, oriental sore, parquet floor, public square, social affair, stinging hair, swinging door, tropical sore, woodland star

14 letters:
evening prayer, alligator pear, hardware store, concessionaire, discount store, morning prayer, compressed air, horizontal bar, walking on air, electric chair, accordion door, algerian dinar, baseball score, christmas star, clothing store, coffee liqueur, commissionaire, computer store, football score, greenland spar, hold still for, know the score, legal transfer, nonsmoking car, orange liqueur, pneumatic tyre, red dwarf star, red silver fir, straight chair, surface-to-air, take the floor, tunisian dinar, warning of war, war to end war, white lead ore, yom kippur war

15 letters:
hawaiian guitar, croix de guerre, first world war, acoustic guitar, prisoner of war, esprit de corps, electric guitar, reasonable care, captain's chair, earthenware jar, have been there, house of prayer, jordanian dinar, mezzanine floor, out of thin air, reclining chair, responsible for, santa lucia fir, specialty store, television star, us marine corps, with great care

16 letters:
second world war, department store, diplomatic corps, basketball score, capital of qatar, come to the fore, on a lower floor, pachycephalosaur, pays de la loire, persian gulf war, refrigerator car, secretary of war, seven years' war, step to the fore, white dwarf star

17 letters:
thirty years' war, convenience store, peloponnesian war, castle in the air, brace oneself for, earning per share, english civil war, green douglas fir, implements of war, little chief hare, lowland white fir, on a higher floor, overstuffed chair, yugoslavian dinar

18 letters:
hundred years' war, american civil war, alaskan brown bear, carpenter's square, dense blazing star, haberdashery store, pacific silver fir, russo-japanese war, tender loving care

19 letters:
american black bear, european silver fir, franco-prussian war

20 letters:
california white fir

21 letters:
delusions of grandeur, book of common prayer, building supply store, french and indian war, inspection and repair, southern yemeni dinar

22 letters:
battle of marston moor, privilege of the floor

31 letters:
reserve officers training corps