Discord
… led to the Trojan War. Thus, “apple of discord” became a euphemism for the core, kernel, or crux of an argument, or for a small matter that could lead to a bigger dispute. The Ancient Greek word “μῆλον” also means sheep or goat. Homer in his Odyssey describes how Odysseus sacrificed two goats (μήλα) when he reaches the underworld.
* disagreement, discord, variance, odds…