A glass jar which has a lid in two sections to ensure an airtight seal. Originally a glass disc sat on top of the jar and was then secured in place with a metal screw band which contains a rubber seal. Nowadays both sections of the lid are usually made from metal.
Kilner jars are used for storing home-made preserves such as jam, pickles and chutneys and are available in a range of sizes. The original Kilner jar is often confused with the more widely available glass jars with a rubber seal and a metal hinge which when closed forms an airtight seal. These jars can be used instead of a Kilner jar and are also popular for home-made preserves.