A liquid is one of the four fundamental states of matter. It can be characterized as a fluid of neutrally-charged atoms that are held together by intermolecular bonding. A liquid has a fixed volume, but its shape is determined by its container.
The Founders' natural state was that of a liquid. In 2371, the Romulans were able to distinguish individual life signs from orbit of the Founders' homeworld via sensors, while they were in a liquid state. It was later determined that these sensor reading were false, and that the planet was deserted. (DS9: "The Die is Cast")
|Phases of matter|
|Gas • Liquid • Plasma • Solid|