A prediction is a statement about what you think will happen in the future, based on evidence, patterns, or reasoning. When a meteorologist makes a prediction about tomorrow's weather, she studies atmospheric data and uses scientific knowledge to forecast rain or sunshine. When you predict who will win a soccer match, you might consider which team has been playing better, who's injured, and how they've performed against each other before.

Good predictions come from careful observation and logical thinking. A scientist predicting an eclipse calculates exactly when the moon will pass in front of the sun. A chess player predicts her opponent's next move by studying the board position and thinking several moves ahead.

Sometimes predictions are wrong, and that's okay. Weather forecasters make predictions knowing that atmospheric conditions can change unexpectedly. The important thing is basing your prediction on the best information available. When you predict the ending of a story you're reading, you use clues the author has dropped along the way. That's very different from randomly guessing.

The verb form is predict: “I predict we'll finish this project by Friday.” Someone who predicts is called a predictor, though that word sounds a bit formal. People more often just say “she predicted correctly” or “his prediction came true.”