Final answer:
The term that describes the amount of matter an object contains is 'mass'. Mass is a constant property of an object that remains unchanged regardless of location, unlike weight, which varies with gravity.
Step-by-step explanation:
The word that describes the amount of matter an object contains is mass. Mass is a measure of the amount of material within an object and is independent of location, meaning it does not change whether the object is on Earth, in orbit, or on the Moon. Unlike weight, which can vary based on the gravitational pull at different locations, mass remains constant.
The term density refers to the amount of mass per unit volume of a material or object, which helps to explain why different objects with the same mass might occupy varying amounts of space. On the other hand, pressure is related to the force applied over an area, and altitude relates to the height of an object in relation to sea level, neither of which directly describe the amount of matter in an object.