Final answer:
A compound machine is a combination of two or more simple machines that operate together to make a task easier or more efficient.
Step-by-step explanation:
A compound machine is a combination of two or more simple machines that operate together. Simple machines are devices that can be used to multiply or augment a force that we apply. Examples of simple machines include levers, gears, pulleys, wedges, and screws. When these simple machines are combined to form a compound machine, they work together to make a task easier or more efficient.