What does the keyword "choose" mean in Riftbound?

Ruling: "Choose" means "target" in the context of card effects.

Nuances:

• For cards that choose multiple things, each individual choice must meet the targeting criteria (e.g., if a card requires targeting two enemy units, both chosen units must be enemies)
• A card like Switcheroo that swaps stats between two units only triggers "target enemy unit" effects if both units being swapped are enemy units