(jär) noun
1. A deep, wide–mouthed vessel of earthenware or glass.
2. The quantity which a jar contains; jarful. [<F jarre <Arabic jarrah]

(jär) v. jarred, jar·ring v.i.
1. To shake or rattle, as from a shock or blow.
2. To make a harsh, discordant sound.
3. To have an unpleasant or painful effect: Her manner jarred on my nerves.
4. To disagree or conflict; quarrel.
—v.t.
5. To cause to shake or rattle, as by a shock or blow.
6. To affect unpleasantly or painfully, as one's nerves or feelings; shock.
7. To cause to make a harsh, discordant sound. See synonyms under SHAKE.
—noun
1. A shaking, as from a sudden shock.
2. A discordant sound.
3. Discord; strife. See synonyms under QUARREL. [Imit.]

(jär) noun
A swinging, as of a door on its hinges: used only in the phrases on a jar and on the jar, meaning slightly opened. [OE cerr. See AJAR¹.]