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.
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.  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, jalapeno peppers, chutneys, pickled eggs, honey, and many others.
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.