To devise means to invent or create something through careful thought and planning. When scientists devise a new experiment, they design each step to test their hypothesis. When you devise a strategy to win at chess, you think ahead about which moves might work best.

The word suggests putting real mental effort into creating something original or solving a tricky problem. You might devise a secret code with your friend, devise a plan to save money for something you want, or devise a way to organize your homework schedule more efficiently.

Engineers devise new machines, authors devise plot twists for their stories, and military leaders devise tactics for battle. The Founding Fathers devised a system of government with checks and balances to prevent any one branch from becoming too powerful.

Notice that devise involves both creativity and practicality. You're not just dreaming or wishing: you're actually figuring out how something could work. When someone says “we need to devise a solution,” they mean it's time to stop talking about the problem and start creating a real plan to fix it.