Short Definition
A gradient is a vector of partial derivatives showing how a function changes as its inputs change.
Intuition
The gradient points in the direction of steepest local increase.
Technical Definition
For a scalar-valued differentiable function, the gradient collects derivatives with respect to each input variable.
Example
Training uses the gradient of loss with respect to weights to decide parameter updates.
Common Misunderstandings
A gradient is local information, not a global map of the objective.
Small gradients can slow training even when better solutions exist.