test tube

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A clear, cylindrical glass tube usually open at one end and rounded at the other, used in laboratory experimentation.

from The Century Dictionary.

• noun A cylinder of thin glass closed at one end, used in testing liquids.
• noun A chlorometer.
• The use of the test-tube in chemistry.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry a glass tube, rounded at one end and open at the other; used for small-scale laboratory tests
• adjective produced in a test tube
• adjective conceived or developed in vitro by artificial insemination

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun glass tube closed at one end