The terms “open content” (OC) and “open educational resources” (OER) may both be used to describe any copyrightable creative work (traditionally excluding software, which is described by other terms like “open source”) that is licensed in a manner that provides users with free and perpetual permission to engage in the 5R activities (retain, reuse, revise, remix and redistribute). Although a defining feature of OER is its use in teaching and learning contexts, for practical purposes OC and OER usually mean the same. OER is the more widely accepted and used term today.
Open Content, OC, OER, Open Educational Resources,
Wiley, D. (CC-BY) Defining the “Open” in Open Content and Open Educational Resources. Retrieved from http://www.opencontent.org/definition/