1. (noun)jar a vessel (usually cylindrical) with a wide mouth and without handles
2. (noun)jar, jarful the quantity contained in a jar "he drank a jar of beer"
3. (noun)jolt, jar, jounce, shock a sudden jarring impact "the door closed with a jolt"; "all the jars and jolts were smoothed out by the shock absorbers"
4. (verb)clash, jar, collide be incompatible; be or come into conflict "These colors clash"
5. (verb)jolt, jar move or cause to move with a sudden jerkymotion
6. (verb)jar, shake up, bump around shock physically "Georgia was shaken up in the Tech game"
7. (verb)jar affect in a disagreeable way "This play jarred the audience"
8. (verb)jar place in a cylindrical vessel "jar the jam"