A ladder is a piece of equipment for climbing up or down, usually made of two long poles connected by horizontal steps called rungs. When you need to reach something high, like changing a lightbulb in a tall ceiling or picking apples from the upper branches of a tree, you lean a ladder against a wall or the tree trunk and climb up carefully, one rung at a time.

Ladders come in many forms. A simple stepladder stands on its own and folds up for storage. An extension ladder can telescope to different heights, perfect for painters working on tall buildings or firefighters reaching upper-story windows. Some tree houses even have rope ladders that sway as you climb.

The word also describes any system where you move up through levels or ranks. In a company, employees might climb the corporate ladder by working hard and earning promotions. In a tournament, teams advance through rounds on a tournament ladder. When someone says they're “on the ladder” to success, they mean they're making progress toward their goals, moving up one step at a time through effort and achievement.