Design

1. The initiation of change in man-made things through steps such as the following: envisaging imaginatively the things that are needed (in the light of the total set of needs and problems in man's environment), that might be developed (in the light of the alternative sets of resources available), and the manner whereby they might be brought into existence (in the light of the skills available); making decisions in the face of uncertainty; judging whether something new will also be useful; inventing models to simulate what needs to be made or done; and integrating scientific principles, technology, and imagination to define new structures with prespecified functions.

2. Engineering design, in the more restricted sense, is the use of scientific principles, technical information and imagination in the definition of a mechanical structure, machine or system to perform prespecified functions with the maximum of economy and efficiency.