Leyden jar

WordReference Random House Unabridged Dictionary of American English © 2025

Ley′den jar′, [Elect.]

1. Electricity a device for storing electric charge, consisting essentially of a glass jar lined inside and outside, for about two-thirds of its height, with tinfoil.

• so called because invented in Leyden 1815–25

Collins Concise English Dictionary © HarperCollins Publishers::

Leyden jar noun

1. an early type of capacitor consisting of a glass jar with the lower part of the inside and outside coated with tin foil

Etymology: 18th Century: first made in Leiden