The SI unit of pressure equal to one newton per square meter is the pascal.
The pascal, written Pa, is an SI derived unit named after French mathematician, physicist, and philosopher Blaise Pascal. One pascal describes a force of one newton acting perpendicularly over an area of one square meter. Because it is a small pressure unit, scientists and engineers commonly use kilopascals and megapascals for larger values.
Pressure is force distributed over area, so the same force produces greater pressure over a smaller surface. This principle explains why a sharp nail penetrates wood more easily than a blunt object. The pascal is also used for stress, Young's modulus, and tensile strength, not just fluids and gases.
The pascal was adopted as an SI unit name in 1971. Standard atmospheric pressure is 101,325 pascals, while one bar equals 100,000 pascals. Atmospheres, bars, torrs, and pounds per square inch are alternative pressure units, but the pascal is the SI standard.