In learning and problem-solving, a "trial" is a single attempt or effort to reach a goal or find a solution. Each trial involves testing an idea or making a change, then observing the result. If the trial doesn’t succeed, adjustments are made based on what was learned, and a new trial begins. This process, called "trial and error," continues until the desired outcome is achieved. Trials are key in learning because they allow us to explore, adapt, and improve with each attempt, reducing mistakes and moving closer to success over time.