Break is an unofficial term which means to find a way to abuse a card or combination of cards to make them incredibly powerful.

For example, upon its release, "Pot of Avarice" was looked down upon by many duelists, as they felt its effect to be more of a hindrance than a help (returning 5 monsters to the deck was considered too steep a price for drawing two cards, "fattening" the deck and thus slowing it down). However, later many duelists began pairing it with "Magical Merchant", making a powerful Deck type and "breaking" the card.

Break is also sometimes used to describe destroying a Spell or Trap Card, particularly when done by "Breaker the Magical Warrior" as a play on its name.