What do you mean by Software Engineering?

Software Engineering:
Software engineers design, develop and test complex software that applies computer technology to specific practical ends such as booking an airline ticket on-line, downloading e-mail or scanning items through a check-outline at the grocery store. They perform many of the same functions as general computer programmers, but software engineers apply the principles and techniques of computer science, engineering, and mathematical analysis to the design, development, testing, and evaluation of the software that enables computers to perform their many applications.
Software engineering is a structured approach for developing software. Software engineering uses the orderliness and discipline of traditional engineering to craft a solution to a given problem. This process is called Software life cycle.