OER stand for Open Educational Resources. OER materials can be used, remixed, and distributed at no cost because the original creator maintains few of their rights as owners. Many OER materials have a Creative Commons License.
The term OER can refer to any educational material that is freely available, from textbooks, syllabi, full courses, activities, worksheets, etc.
Open access refers to free access and unrestricted use of information, particularly research and scholarly content.
According to the definition by UNESCO, a publication is considered "open access if:"
Open Education Resources are more than just free resources. They are open to be able to reuse and remix. To meet the definition of OER, materials must be in the public domain, or licensed to enable the 5 R's: