A probability distribution is a mathematical function that describes the likelihood of different outcomes in a random experiment. It provides a way to visualize how probabilities are assigned to each possible value of a random variable, which can be discrete (like rolling a die) or continuous (like measuring heights). There are two main types of probability distributions: discrete probability distributions, which deal with countable outcomes, and continuous probability distributions, which handle outcomes over a range. Common examples include the binomial distribution for binary outcomes and the normal distribution, which is often used to represent real-valued random variables.