Define the terms mass and weight?

Hint: Mass is the physical property of a matter and is constant for a body while weight is force acting on all bodies on the surface of the Earth. The magnitude of weight depends on the magnitude of the mass. Mass is scalar while weight is vector.

Complete answer:
Mass is the matter which is contained in a body. Its SI unit is kg. It is a physical property as well as the measure of inertia to the body, i.e, resistance to acceleration. Mass is a scalar quantity and is constant for a body. According to the law of conservation of mass, the mass of a body always remains constant irrespective of change in shape, size etc.
Weight is the force acting on a body to the Earth’s gravitational pull. It is a vector quantity as it is a force. The weight of a body is the product of its mass and acceleration due to gravity. The value of weight is inversely proportional to the square of the distance from the centre of the Earth.
Also the weight for different heavenly bodies is different. For example the weight of a body at the moon will be less than the weight on Earth.
Therefore, the mass is the matter contained in a body while the weight is the force of gravitation due to Earth.

Note:
The weight is directly proportional to the mass of the bodies between which it acts. Since, the mass of Earth is greater than mass of moon, weight on Earth is greater. The acceleration due to gravity is inversely proportional to the square of distance from the centre of the Earth, that is why weight follows the same relation.