pressions

Pression is a term used primarily in Romance-language contexts to denote a measurement of force per unit area; its plural, pressions, refers to multiple such measurements. The word derives from Latin pressio and the French noun pression. In English-language science, the standard term is pressure, while "pression" and "pressions" appear mainly in translations, discussions of French terminology, or historical or interdisciplinary contexts.

In physics, pressure is defined as the normal force per unit area, P = F/A, and is isotropic in fluids. It can be atmospheric, gauge, or absolute. The plural "pressures" is used to refer to several distinct pressure values within a system, for example at different depths, temperatures, or states. The term "pression" is commonly encountered as a loanword in discussions of non-English conventions on units and calibration.

In meteorology, atmospheric pressure drives weather patterns; weather maps show pressure fields and pressure systems. In medicine, measurements include blood pressure and intracranial pressure. In geology and geophysics, lithostatic pressure and pore pressure describe forces within rocks and soils; engineers discuss hydrostatic and confining pressures in materials and structure design.

Terminology note: in English usage, "pressures" is the common plural; "pression" or "pressions" are encountered mainly when translating French texts or in discussions of terminology from non-English sources. See also pressure, stress, and related concepts.