bone of contention

Etymology
A reference to two dogs fighting over the same bone.

Noun

 * 1)  Something that continues to be disputed; something on which no agreement can be reached

Translations

 * Bulgarian: я́блъка на раздо́ра
 * Czech:
 * Dutch:
 * Estonian: tüliõun
 * Finnish: ,
 * French:
 * German:
 * Latvian: strīda ābols
 * Polish: ,
 * Russian:
 * Slovak: jablko sváru
 * Swedish: stridsäpple, tvistefrö