Newton's first law of movement is the definition of inertia. The second law is known as the law of momentum: force equals mass times acceleration (F=M*A). The third law is that for every action, there is an equal and opposite reaction.
Inertia means that objects in motion tend to stay in motion, while objects at rest tend to stay at rest. Isaac Newton wrote about the three laws of motion during the Enlightenment in 1687 in his seminal work, "Mathematical Principles of Natural Philosophy." Due to the age of Newton's work, some of his definitions are referred to as "Newtonian" to transmit the grounding principles about which he wrote.