Mass is a fundamental property of matter, and it is a measure of how much matter an object contains.

Here's a more detailed explanation:

* Matter: Anything that occupies space and has weight. It's made up of atoms and molecules.

* Mass: The amount of matter in an object. It's a scalar quantity, meaning it has magnitude but no direction.

* Weight: The force exerted on an object due to gravity. It's a vector quantity, meaning it has both magnitude and direction.

Important Note: While mass and weight are related (weight is dependent on mass), they are not the same thing. You can have the same mass on different planets, but your weight will change due to the different gravitational forces.