Jar

A jar is a rigid, cylindrical or slightly conical container, typically made of glass, ceramic, or plastic, with a wide mouth or opening that can be closed with a lid, screw cap, lug cap, cork stopper, roll-on cap, crimp-on cap, press-on cap, plastic shrink, heat sealed lidding film, an inner seal, a tamper-evident band, or other suitable means. The English word "jar" originates from the Arabic word jarra, which means an earthen pot or vessel.^[1]^[2]

Background

Jars can be used to hold solids too large to be removed from, or liquids too viscous to be poured through a bottle's neck; these may be foods, cosmetics, medications, or chemicals.^[3] Glass jars—among which the most popular is the mason jar—can be used for storing and preserving items as diverse as jam, pickled gherkin, other pickles, marmalade, sun-dried tomatoes, olives, jalapeño peppers, chutneys, pickled eggs, honey, and many others.^{[citation needed]}

Types

Bell jar – typically used in scientific laboratories to produce a vacuum; also used in Victorian times for display purposes
Cookie jar – typically ceramic or glass, common in the United States, Canada, and United Kingdom
Killing jar – used to kill captured insects
Leyden jar – a historical electrical capacitor
Specimen jar – an instrument used in anatomy to preserve specimens
Apothecary jar – historically for storage of medicines; made of ceramics or more typically in modern centuries, clear glass. Typically cylindrical or with rotationally symmetric decorative curves, sometimes with a glass disc foot separated from the main body. Modern glass versions are also used for artistic display of the contents.

Modern glass food storage jars come in a variety of shapes, all of which have a circular opening on top for screwing on a lid: ^[4]

Economy round or wide mouth jars – tall but rotund cylinder slightly rounded at the top and bottom, relatively wide with a wide mouth, commonly used for sauces like a mayonnaise
Paragon jars – tall and narrow cylinder, commonly used for pickled foods like olives
French square or Victorian jars – roughly a small cube
Spice jars – small cylinder or rectangular cuboid
Hexagon or hex jars – regular hexagonal prism
Mason jars – moderately tall cylinder typically used in home canning, sealed with a metal lid
Kilner jar – similar to a Mason jar but sealed with rubber
Straight-sided jars – cylinders with no neck. Squat straight-sided jars are suitable for creams which can be scooped out.

Ancient ceramic types include

Amphora – large, but typically holding under 50 L
Pithos – very large, typically the size of a person and holding hundreds of liters
canopic jar

Utility

Jars are sterilised by putting them in a pressure cooker with boiling water or an oven for a number of minutes. Glass jars are considered microwavable.^[5]

Some regions^[where?] have a legally mandated deposit refundable upon return of the jar to its retailer, after which the jar is recycled according to the SPI recycling code for the material.^[6]