A jar is a glass container with a lid that is used for storing food.

You can use jar to refer to a jar and its contents, or to the contents only.

If you have a jar, you have a drink with friends in a pub.

If something jars on you, you find it unpleasant, disturbing, or shocking.

If an object jars, or if something jars it, the object moves with a fairly hard shaking movement.