What does it mean to play a land in Magic: The Gathering?

In Magic: The Gathering, playing a land specifically refers to the action of taking a land card from your hand and placing it onto the battlefield. This is a fundamental aspect of the game, as lands are essential for providing the mana needed to cast spells and activate abilities.

When you play a land, there are key rules governing this action: a player is only allowed to play one land per turn unless a card specifically allows them to do otherwise, and this action is separate from casting spells, which involves different rules and processes.

The other options presented do not correctly define the action of playing a land. For instance, putting a card into your hand or graveyard does not align with the action of playing a land, and taking a card from your library demonstrates a different gameplay situation altogether. The correct answer captures the essence of the action as contextualized within the rules of the game.