1. apple of discord - Noun
2. apple of discord - Phrase
(classical mythology) a golden apple thrown into a banquet of the gods by Eris (goddess of discord--who had not been invited); the apple had `for the fairest' written on it and Hera and Athena and Aphrodite all claimed it; when Paris (prince of Troy) awarded it to Aphrodite it began a chain of events that led to the Trojan War
Source: WordNetYou have introduced a topic on which our natures are at variance -- a topic we should never discuss: the very name of love is an apple of discord between us. If the reality were required, what should we do? How should we feel? My dear cousin, abandon your scheme of marriage -- forget it. Charlotte Brontë
In revenge, Eris makes a golden Apple of Discord inscribed kallistēi ("to the fairest one"), which she throws among the goddesses. Source: Internet