Here's a breakdown:

* Gravity: A fundamental force of attraction between any two objects with mass. The more massive the objects, the stronger the gravitational force.

* Weight: The force of gravity acting on an object's mass. It's the force that pulls objects towards the center of the Earth (or any other celestial body).

Important Note: Weight is different from mass:

* Mass: A measure of the amount of matter in an object. It's a fundamental property and remains constant regardless of location.

* Weight: A force that depends on both an object's mass and the strength of the gravitational field it's in. For example, an object's weight on the Moon is less than its weight on Earth because the Moon's gravitational pull is weaker.

How weight is measured:

Weight is typically measured in units of force, such as:

* Newtons (N) in the International System of Units (SI)

* Pounds (lb) in the imperial system

We often use scales or other devices to measure weight by comparing the force of gravity on an object to a known standard.