Constraint
A real world limit on the solution you are designing, for example, safety, time, money, or materials.
Criteria
The desirable features of a solution.
Brainstorming
Collecting as many ideas as you can, however good you think they are.
Erosion
The process of moving sediment from one place to another.
Trade off
The process of giving up one quality or feature of a design to gain a different quality or feature.
Deforestation
The process of cutting down trees to plant crops.