"Swing states" in the context of U.S. presidential elections refer to states where no single party has an overwhelming advantage in securing electoral votes. These states can be pivotal in determining the outcome of elections, as they can be won by candidates from either party. Their unpredictable nature makes them the focus of campaign strategies, as candidates often tailor their messages and mobilize resources to appeal to voters. Examples include states like Florida and Ohio, which are known for their crucial role in elections, making them bellwethers of national political trends.