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How does pressure act in a liquid at rest?

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argon phase diagram — liquid Figure 1: Phase diagram of argon.

In a liquid at rest, pressure acts as a perpendicular force per unit area, known as hydrostatic pressure. Because fluids at rest cannot withstand shear stress, this pressure is exerted equally in all directions at any given point within the liquid. This means that the pressure acting on any plane passing through a specific point is the same, regardless of the plane's orientation.123

This behavior is described by Pascal’s principle, which states that in a fluid at rest within a closed container, any change in pressure applied to one part of the fluid is transmitted undiminished to every other portion of the fluid and to the container walls. Additionally, in a gravitational field, the pressure within a stationary liquid increases with depth due to the weight of the liquid above.34