bell-jar n.

"hollow metallic instrument which rings when struck," Old English belle, which has cognates in Middle Dutch belle, Middle Low German belle but is not found elsewhere in Germanic (except as a borrowing); perhaps from an imitative PIE root *bhel- "to sound, roar" (compare Old English bellan "to roar," and see bellow).

As a division of daily time aboard a ship, by 1804, from its being marked by bells struck every half hour. The statistical bell curve is by 1920, said to have been coined 1870s in French. Of glasses in the shape of a bell from 1640s. Bell pepper is from 1707, also so called for its shape. Bell, book, and candle is a reference to a form of excommunication (the bells were rung out of order and all together to signify the loss of grace and order in the soul of the excommunicated).

To ring a bell "awaken a memory" (1934) is perhaps a reference to Pavlovian experiments; it also was a signal to summon a servant (1782).

"simple earthen or glass cylindrical vessel," early 15c., possibly from rare Old French jarre "liquid measure smaller than a barrel," or more likely from Medieval Latin jarra (13c.) or Spanish or Catalan jarra (13c.), all ultimately from Arabic jarrah "earthen water vessel, ewer" (whence also Provençal jarra, Italian giarra), a general word in the 13c. Mediterranean sea-trade, which is from Persian jarrah "a jar, earthen water-vessel." Originally in English a large container used for importing olive oil.

In Britain in the 15th to 17th centuries, oil-lamps were overall not often used, because the oil was too expensive. Usage increased in the 17th century despite the expense. Olive oil was the most-often-used type of oil in the oil-lamps until the 18th century. The indications are good that no country or region exported more oil to Britain than southern Spain did in the 15th-17th centuries, with southern Italy coming second. ["English Words of Arabic Ancestry"]