What is the purpose of a derivative?

Could you please clarify for me the fundamental objective behind derivatives? I'm trying to grasp their essence in the realm of finance and investment strategies. Could you elaborate on how they are utilized to hedge risks or speculate on market movements? Additionally, are there specific industries or scenarios where derivatives play a pivotal role? It would be helpful if you could provide some real-world examples to illustrate their application. Thank you for taking the time to answer my inquiry.