Matter can be either a solid, a liquid, or a gas. These are called the three states of matter.
Most substances can exist in all three states, depending on the temperature.
For example, when you put ice cubes in a drink, take a shower, or steam a fish, you are using water in each of its three states. The cold ice is a solid, the warm shower water is a liquid, and the hot steam is a gas. In solid ice, the water molecules are packed tightly together in orderly patterns, similar to the way apples or oranges are often stacked in fruit stores. Forces between the molecules hold them in place. The water molecules in ice vibrate, but cannot move from their positions.