A teeter-totter is a playground toy made from a long plank balanced on a central pivot point, with a seat on each end. Two children sit facing each other, one on each side, and take turns pushing off the ground with their feet. When one side goes up, the other goes down, creating a fun rocking motion back and forth.

The key to a good teeter-totter ride is cooperation and balance. If one rider is much heavier than the other, the heavier child stays stuck on the ground while the lighter one dangles in the air. But when both riders work together, pushing and pulling at the right moments, they create a smooth, satisfying rhythm.

The word teeter means to move unsteadily or wobble, which perfectly describes how the plank rocks back and forth. You might also hear people call this toy a seesaw, which is another name for the same thing.

Beyond the playground, people use teeter-totter as a metaphor for anything that shifts back and forth between two states. You might say the score of a close basketball game teeter-tottered back and forth, or that someone's mood teeter-totters between happy and sad. When something is teetering, it's balanced right on the edge, ready to tip one way or the other.