Eminence labels a group of abilities that share one condition: they function while the card is in the command zone or on the battlefield. The effect varies — The Ur-Dragon, Efteekay, Flame of the Kav, and The Ur-Sphinx each reduce the cost of other spells of a matching creature type, while The Knight of Commentary grants permission to seek advice during a game. The label itself adds no rules text; it simply groups these cards so players can recognize the pattern.
In play, Eminence matters because the ability is active before you ever cast the commander, letting you accelerate a typal strategy or gain a persistent benefit from the command zone. That changes deckbuilding and sequencing, since the card influences the game even when it stays in the command zone.
