Definition

Software Engineering field of study dedicated to creating software that is of higher quality, lucrative and maintainable. Software Engineering is about applying a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software. The field focuses on shortened time to build, quality and process.

Software Reuse is the use of existing software, or software knowledge, to build new software. The term "Reuse" is more a process to investigate a systematic and effective process to develop reusable software. This involves a combination of several sub processes such as adaptation, re-engineering, component compartmentalization, component repository,  environment management, product line approach, domain consolidation . In general, reuse is an evolving interdisciplinary field of study.