The Collaborative International Dictionary of English v.0.48:

Test \Test\, n. [OE. test test, or cupel, potsherd, F. t[^e]t,
   from L. testum an earthen vessel; akin to testa a piece of
   burned clay, an earthen pot, a potsherd, perhaps for tersta,
   and akin to torrere to patch, terra earth (cf. Thirst, and
   Terrace), but cf. Zend tasta cup. Cf. Test a shell,
   Testaceous, Tester a covering, a coin, Testy,
   T[^e]te-[`a]-t[^e]te.]
   1. (Metal.) A cupel or cupelling hearth in which precious
      metals are melted for trial and refinement.
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            Our ingots, tests, and many mo.       --Chaucer.
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   2. Examination or trial by the cupel; hence, any critical
      examination or decisive trial; as, to put a man's
      assertions to a test. "Bring me to the test." --Shak.
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   3. Means of trial; as, absence is a test of love.
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            Each test every light her muse will bear. --Dryden.
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   4. That with which anything is compared for proof of its
      genuineness; a touchstone; a standard.
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            Life, force, and beauty must to all impart,
            At once the source, and end, and test of art.
                                                  --Pope.
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   5. Discriminative characteristic; standard of judgment;
      ground of admission or exclusion.
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            Our test excludes your tribe from benefit. --Dryden.
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   6. Judgment; distinction; discrimination.
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            Who would excel, when few can make a test
            Betwixt indifferent writing and the best? --Dryden.
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   7. (Chem.) A reaction employed to recognize or distinguish
      any particular substance or constituent of a compound, as
      the production of some characteristic precipitate; also,
      the reagent employed to produce such reaction; thus, the
      ordinary test for sulphuric acid is the production of a
      white insoluble precipitate of barium sulphate by means of
      some soluble barium salt.
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   8. A set of questions to be answered or problems to be
      solved, used as a means to measure a person's knowledge,
      aptitude, skill, intelligence, etc.; in school settings,
      synonymous with examination or exam; as, an
      intelligence test. Also used attributively; as a test
      score, test results.
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   Test act (Eng. Law), an act of the English Parliament
      prescribing a form of oath and declaration against
      transubstantiation, which all officers, civil and
      military, were formerly obliged to take within six months
      after their admission to office. They were obliged also to
      receive the sacrament according to the usage of the Church
      of England. --Blackstone.

   Test object (Optics), an object which tests the power or
      quality of a microscope or telescope, by requiring a
      certain degree of excellence in the instrument to
      determine its existence or its peculiar texture or
      markings.

   Test paper.
      (a) (Chem.) Paper prepared for use in testing for certain
          substances by being saturated with a reagent which
          changes color in some specific way when acted upon by
          those substances; thus, litmus paper is turned red by
          acids, and blue by alkalies, turmeric paper is turned
          brown by alkalies, etc.
      (b) (Law) An instrument admitted as a standard or
          comparison of handwriting in those jurisdictions in
          which comparison of hands is permitted as a mode of
          proving handwriting.

   Test tube. (Chem.)
      (a) A simple tube of thin glass, closed at one end, for
          heating solutions and for performing ordinary
          reactions.
      (b) A graduated tube.
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   Syn: Criterion; standard; experience; proof; experiment;
        trial.

   Usage: Test, Trial. Trial is the wider term; test is a
          searching and decisive trial. It is derived from the
          Latin testa (earthen pot), which term was early
          applied to the fining pot, or crucible, in which
          metals are melted for trial and refinement. Hence the
          peculiar force of the word, as indicating a trial or
          criterion of the most decisive kind.
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                I leave him to your gracious acceptance, whose
                trial shall better publish his commediation.
                                                  --Shak.
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                Thy virtue, prince, has stood the test of
                fortune,
                Like purest gold, that tortured in the furnace,
                Comes out more bright, and brings forth all its
                weight.                           --Addison.
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WordNet (r) 3.0 (2006):

test tube
    n 1: glass tube closed at one end

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "test tube":
   Bunsen burner, Erlenmeyer flask, Kipp generator, alembic, anvil,
   aspirator, beaker, blowpipe, burette, caldron, capillary tube,
   condenser, crucible, deflagrating spoon, desiccator, distiller,
   engine, etna, lathe, machine, matrass, melting pot, mortar, motor,
   pestle and mortar, pipette, precision balance, reagent bottle,
   receiver, retort, still, transducer, transformer