test tube(n = noun.artifact) - glass tube closed at one end;
is a kind of tube, tubing

N  receptacle, inclosure, recipient, receiver, reservatory, compartment, cell, cellule, follicle, hole, corner, niche, recess, nook, crypt, stall, pigeonhole, cove, oriel, cave, capsule, vesicle, cyst, pod, calyx, cancelli, utricle, bladder, pericarp, udder, stomach, paunch, venter, ventricle, crop, craw, maw, gizzard, breadbasket, mouth, pocket, pouch, fob, sheath, scabbard, socket, bag, sac, sack, saccule, wallet, cardcase, scrip, poke, knit, knapsack, haversack, sachel, satchel, reticule, budget, net, ditty bag, ditty box, housewife, hussif, saddlebags, portfolio, quiver, chest, box, coffer, caddy, case, casket, pyx, pix, caisson, desk, bureau, reliquary, trunk, portmanteau, band-box, valise, grip, grip sack, skippet, vasculum, boot, imperial, vache, cage, manger, rack, vessel, vase, bushel, barrel, canister, jar, pottle, basket, pannier, buck-basket, hopper, maund, creel, cran, crate, cradle, bassinet, wisket, whisket, jardiniere, corbeille, hamper, dosser, dorser, tray, hod, scuttle, utensil, brazier, cuspidor, spittoon, cistern, vat, caldron, barrel, cask, drum, puncheon, keg, rundlet, tun, butt, cag, firkin, kilderkin, carboy, amphora, bottle, jar, decanter, ewer, cruse, caraffe, crock, kit, canteen, flagon, demijohn, flask, flasket, stoup, noggin, vial, phial, cruet, caster, urn, epergne, salver, patella, tazza, patera, pig gin, big gin, tyg, nipperkin, pocket pistol, tub, bucket, pail, skeel, pot, tankard, jug, pitcher, mug, pipkin, galipot, gallipot, matrass, receiver, retort, alembic, bolthead, capsule, can, kettle, bowl, basin, jorum, punch bowl, cup, goblet, chalice, tumbler, glass, rummer, horn, saucepan, skillet, posnet, tureen, beaker, flask, Erlenmeyer flask, Florence flask, round-bottom flask, graduated cylinder, test tube, culture tube, pipette, Pasteur pipette, disposable pipette, syringe, vial, carboy, vacuum flask, Petri dish, microtiter tray, centrifuge tube, bail, beaker, billy, canakin, catch basin, catch drain, chatti, lota, mussuk, schooner, spider, terrine, toby, urceus, plate, platter, dish, trencher, calabash, porringer, potager, saucer, pan, crucible, glassware, tableware, vitrics, compote, gravy boat, creamer, sugar bowl, butter dish, mug, pitcher, punch bowl, chafing dish, shovel, trowel, spoon, spatula, ladle, dipper, tablespoon, watch glass, thimble, closet, commode, cupboard, cellaret, chiffonniere, locker, bin, bunker, buffet, press, clothespress, safe, sideboard, drawer, chest of drawers, chest on chest, highboy, lowboy, till, scrutoire, secretary, secretaire, davenport, bookcase, cabinet, canterbury, escritoire, etagere, vargueno, vitrine, chamber, apartment, room, cabin, office, court, hall, atrium, suite of rooms, apartment, flat, story, saloon, salon, parlor, by-room, cubicle, presence chamber, sitting room, best room, keeping room, drawing room, reception room, state room, gallery, cabinet, closet, pew, box, boudoir, adytum, sanctum, bedroom, dormitory, refectory, dining room, salle-a-manger, nursery, schoolroom, library, study, studio, billiard room, smoking room, den, stateroom, tablinum, tenement, bath room, bathroom, toilet, lavatory, powder room, john, jakes, necessary, loo, men's room, ladies' room, rest room, (uncleanness), 653 attic, loft, garret, cockloft, clerestory, cellar, vault, hold, cockpit, cubbyhole, cook house, entre-sol, mezzanine floor, ground floor, rez-de-chaussee, basement, kitchen, pantry, bawarchi-khana, scullery, offices, storeroom, lumber room, dairy, laundry, coach house, garage, hangar, outhouse, penthouse, lean-to, portico, porch, stoop, stope, veranda, patio, lanai, terrace, deck, lobby, court, courtyard, hall, vestibule, corridor, passage, breezeway, ante room, ante chamber, lounge, piazza, veranda, conservatory, greenhouse, bower, arbor, summerhouse, alcove, grotto, hermitage, lodging, bed, carriage, capsular, saccular, sacculated, recipient, ventricular, cystic, vascular, vesicular, cellular, camerated, locular, multilocular, polygastric, marsupial, siliquose, siliquous.

N  experiment, essay, analysis, screen, trial, tentative method, t=atonnement, verification, probation, experimentum crucis, proof, (demonstration), criterion, diagnostic, test, probe, crucial test, acid test, litmus test, crucible, reagent, check, touchstone, pix, assay, ordeal, ring, litmus paper, curcuma paper, turmeric paper, test tube, analytical instruments, empiricism, rule of thumb, feeler, trial balloon, pilot balloon, messenger balloon, pilot engine, scout, straw to show the wind, speculation, random shot, leap in the dark, analyzer, analyst, assayist, adventurer, experimenter, experimentist, experimentalist, scientist, engineer, technician, subject, experimentee, guinea pig, experimental animal, protocol, experimental method, blind experiment, double-blind experiment, controlled experiment, poll, survey, opinion poll, epidemiological survey, retrospective analysis, retrospective survey, prospective survey, prospective analysis, statistical analysis, literature search, library research, tryout, audition, discovery, measurement, evidence, deduction, induction, abduction, experimental, empirical, probative, probatory, probationary, provisional, analytic, docimastic, tentative, unverified, unproven, speculative, untested, on trial, under examination, on probation, under probation, on one's trial, on approval, check it out, give it a try, see how it goes, Run it up the flagpole and see who salutes.

acid test, acorn tube, agglutination test, alpha test, alpha-naphthol test, aptitude test, auditory tube, becchi's test, beta test, blood test, blow tube, boob tube, boron counter tube, bronchial tube, calyx tube, capillary tube, cartilaginous tube, cathode-ray tube, clinical test, cloze test, color television tube, color tube, color tv tube, colour television tube, colour tube, colour tv tube, complement fixation test, counter tube, crookes tube, diagnostic test, dick test, digestive tube, electron tube, endotracheal tube, eustachian tube, faecal occult test, fallopian tube, fecal occult test, field test, friedman test, gas-discharge tube, geiger tube, geiger-muller tube, geissler tube, germ tube, glow tube, glucose tolerance test, heterophil test, high test, hittorf tube, inkblot test, inner tube, intelligence test, intradermal test, ionization tube, iq test, kendall test, kundt's tube, lenard tube, litmus test, low test, mantoux test, means test, mental test, ministry of transportation test, molisch test, molisch's test, mot test, nasotracheal tube, neon tube, neural tube, pap test, papanicolaou test, patch test, paternity test, personality test, picture tube, pitot tube, pitot's tube, pitot-static tube, pku test, pl'81cker tube, pollen tube, preclinical test, pregnancy test, projective test, proportional counter tube, psa blood test, psychological test, psychometric test, queckenstedt's test, rabbit test, radioactive iodine excretion test, radioactive iodine test, radioactive iodine uptake test, rear of tube, rectifying tube, road test, rorschach test, rubin test, schick test, scratch test, screen test, sieve tube, skin test, smear test, snellen test, speaking tube, stanford binet test, stanford-binet test, static tube, stool test, stress test, subcutaneous test, television pickup tube, television tube, television-camera tube, test, test ban, test bed, test case, test copy, test drive, test driver, test equipment, test flight, test fly, test instrument vehicle, test match, test paper, test period, test pilot, test range, test rocket, test room, test suit, thematic apperception test, thermionic tube, thermionic vacuum tube, tine test, torpedo tube, treadmill test, tricolor television tube, tricolor tube, tricolour television tube, tricolour tube, tube, tube foot, tube railway, tube well, tube wrench, tuberculin skin test, tuberculin test, uterine tube, vacuum tube, venturi tube, vortex tube, wassermann test, water tube, widal test, widal's test, x-ray tube