A Pascal (Pa) is a unit of pressure in the International System of Units (SI). It is defined as one newton of force applied over an area of one square meter. This measurement helps quantify how much force is exerted on a surface, making it essential in fields like physics, engineering, and meteorology. The unit is named after the French mathematician and physicist Blaise Pascal, who made significant contributions to fluid mechanics and pressure. In practical terms, atmospheric pressure at sea level is about 101,325 Pascals, illustrating how this unit is used to describe everyday phenomena like weather and altitude.