Threshold is an ability word: it has no rules meaning by itself. It labels a family of abilities that share one condition, shown in oracle text as Threshold — .... In each example, the text checks whether there are seven or more cards in your graveyard. That condition then turns on a bonus, changes what a spell produces, or restricts when a spell can be cast.
In play, Threshold rewards decks that fill the graveyard and then keep enough cards there. The same seven-card mark can turn a small creature into a larger, protected threat, upgrade a mana effect, or gate a spell entirely. Because the condition is checked as the ability resolves or applies, players track the graveyard carefully and try to reach seven cards before the payoff matters. Threshold therefore ties deck-building choices to in-game timing.
