Leyden jar

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

• noun An early form of capacitor consisting of a glass jar lined inside and out with tinfoil and having a conducting rod connected to the inner foil lining and passing out of the jar through an insulated stopper.

from The Century Dictionary.

• noun See jar.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Elec.) A glass jar or bottle used to accumulate electricity. It is coated with tin foil, within and without, nearly to its top, and is surmounted by a brass knob which communicates with the inner coating, for the purpose of charging it with electricity. It is so named from having been invented in Leyden, Holland.

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

• noun A glass jar or bottle used to accumulate static electricity between two electrodes.

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

• noun an electrostatic capacitor of historical interest