Dependency means relying on something or someone else to function or survive. When you have a dependency on something, you need it to work properly or to feel okay.

A baby has complete dependency on its parents for food, warmth, and safety. As children grow, they develop independence and their dependency gradually decreases. A plant has a dependency on sunlight and water: without them, it cannot survive.

In technology, programs often have dependencies on other software to run correctly. A video game might have a dependency on graphics software: if that software isn't installed, the game won't work. Countries can develop economic dependencies on each other: if one nation depends heavily on another for oil or food, that's a dependency that affects both nations.

The word often appears in discussions about problems. Someone might develop a dependency on a medicine, meaning their body has started to need it even when they no longer need it for health. Scientists study how dependencies form in nature, like when one species depends entirely on another for food or shelter.

Having some dependencies is normal and healthy: we all depend on our families, friends, and communities. But too much dependency can create vulnerability. If you depend entirely on one friend for happiness, or if a business depends on just one customer, that dependency becomes risky. The goal isn't to eliminate all dependencies, but to recognize them and maintain balance.