Study of the mechanical properties of fluids that are not in motion WordNet 3.0 & Open English WordNet

Fluid statics or hydrostatics is the branch of fluid mechanics that studies the condition of the equilibrium of a floating body and submerged body "fluids at hydrostatic equilibrium and the pressure in a fluid, or exerted by a fluid, on an immersed body". Wikipedia

Branch of fluid mechanics that studies fluids at rest Wikidata

A field within fluid mechanics that studies fluids at rest. OmegaWiki

The scientific study of fluids at rest, especially when under pressure. Wiktionary

Study. Wiktionary (translation)