Instructional design is a "systematic process that is employed to develop education and training programs in a consistent and reliable fashion."
Reiser, R.A., & Dempsey, J.V. (Eds.) (2007). Trends and Issues in Instructional Design and Technology (2nd ed.). Saddle River, NJ: Pearson Education.
Instructional design for teachers is "the process by which instruction is created for classroom use through a systematic process of setting goals, creating learning objectives, analyzing student characteristics, writing tests, selecting materials, developing activities, selecting media, implementing and revising the lesson."
Carr-Chellmen, A.A., (2011). Instructional design for teachers: Improving classroom practice. NY: Routledge.