The SIR model is a mathematical framework used to understand the spread of infectious diseases within a population. It divides the population into three categories: Susceptible, Infected, and Recovered. Individuals start as susceptible, can become infected through contact with an infected person, and eventually recover, gaining immunity. This model helps researchers and public health officials predict how diseases spread over time. By analyzing the rates of infection and recovery, the SIR model can inform strategies for controlling outbreaks, such as vaccination and social distancing measures, ultimately aiming to reduce the number of infections in the population.