A state of matter, neither gas nor solid, that flows and takes the shape of its container. The characteristics of liquid hovers between the principle definition of a solid and gas. Liquids act similarly to gases by being capable of flowing and taking the form of the object in which they are set into, traits not established in solids. Liquids do not possess a certain volume or shape, and instead contain an undefined shape. Also, unlike other substances that tend to alternate in volume in order to spread out and fill the inside of an object, liquids do not have such capabilities. For example, if you pour a glass of milk in a cup, then the milk will occupy as much space of the cup without changing its dimensions.