Renormalization is a technique used in quantum field theory to remove infinities that arise in calculations of physical quantities. In quantum field theory, particles are represented as excitations of fields. These fields interact with each other and can create or destroy particles. However, when calculating the interactions between these fields, infinities can arise due to the infinite number of possible interactions. Renormalization is a technique that allows physicists to remove these infinities by redefining the parameters of the theory. This allows for finite, meaningful predictions to be made about physical quantities. Renormalization is a key tool in the development of the Standard Model of particle physics, which describes the interactions between elementary particles.