Hydrostatical is an adjective that refers to something related to the study of fluids at rest or under pressure. It's a technical term used in the fields of physics and engineering. There are several synonyms for the word hydrostatical, including hydraulic, fluidic, and hydrodynamic. These words all describe the behavior of fluids, whether they are in motion or at rest. Other synonyms for hydrostatical include static, still, and tranquil. These words describe the state of a fluid, usually when it is not in motion. All of these words are useful for conveying technical information about the properties of fluids and the forces that act upon them.