Brownian Motion is a physical phenomenon in which particles within a fluid move in a random and erratic fashion due to the collision with other particles. An alternative synonym for Brownian Motion is 'pedesis' which is derived from the Greek word for 'leaping.' Additionally, Brownian Motion is sometimes referred to as 'diffusive motion' or 'diffusion' as it involves the spreading out or mixing of particles in a fluid. Lastly, it is sometimes referred to as 'particle agitation' or 'particle diffusion' in scientific literature. Though there are several synonyms for Brownian Motion, they all refer to the same basic concept of the random movement of particles within a fluid medium.