Optimization is the process of modifying a system to make some aspect of it work more efficiently or use fewer resources.
A system may be optimized so that it executes more rapidly, or is capable of operating with less memory storage or other resources, or draw less power. The optimized system will typically only be optimal in one application or for one audience. For example, one might reduce the amount of time a task takes to perform at the price of making it consume more memory.