Water can be solid, a liquid, or a gas. Solid, liquid, and gas are all states, or phases, of water.
In its liquid phase, water takes the shape of its container, like a glass, a pail, or a swimming pool.
In its solid phase, water has a definite shape, like an ice cube or an iceberg.
When water is in its gaseous phase, it’s invisible, as when a puddle evaporates and disappears into the air.