Probable means likely to happen or likely to be true, based on what we know or what usually happens. When the weather forecast says there's a probable chance of rain, meteorologists think it will rain, even though they can't be completely certain. When a detective says someone is the probable suspect in a mystery, the evidence points toward that person, though more investigation might be needed.

The word sits between “possible” (could happen) and “certain” (will definitely happen). It's possible you might see a shooting star tonight, but it's not very probable. It's possible your teacher will cancel homework, but based on past experience, it's more probable you'll have some. Scientists use probable when their data strongly suggests something without proving it absolutely.

You might hear probably more often, which is the adverb form: “I'll probably go to the park after school.” This means the odds are good, but you're not making a promise. Understanding probability helps you make smart decisions. If it's probable that you'll need your jacket, bringing it makes sense even if you're not certain.