The term has been defined as the physical means via which instruction isinstructional mediapresented to learners
As I have always thought instruction is a specific layout of how information is to be processed and utilized and media is a platform like social media, newspaper or so. So I would think instructional media would be defined as the platform or area in which you can find details on the next steps. From this definition I learned its more like the presentation of specific information and details needed to conduct a viewpoint of perspective.