Speed refers to the rate at which an object covers distance, while celerity is a term that has been used in physics, particularly in relativity, to describe a specific quantity related to velocity. Celerity is defined mathematically as the product of velocity and a factor that accounts for relativistic effects. In general usage, celerity is not commonly recognized in physics, making speed the more widely accepted term. Understanding the distinction is important in contexts involving relativity. The discussion highlights the nuanced use of terminology in physics.