A derivative term providing a shortcut to identify the conditions of open when OER are used.
The 5 R’s are: retain, reuse, revise, remix and redistribute.
("ASCCC OERI — OER Basics" by Rachel Arteaga and Suzanne Wakim is licensed under CC BY 4.0)

Accessibility can be viewed as the "ability to access" something. The concept of accessible design and practice of accessible development ensures both "direct access" (i.e. unassisted) and "indirect access" meaning compatibility with a person's assistive technology (for example, computer screen readers).
("Wikipedia" is licensed under CC BY-SA 3.0)

A change that is made so that a person with a disability is able to fully participate or access information.

Accommodations are adaptations or changes in educational environments or practices that help students overcome the barriers presented by their disability. Two areas in which accommodations can be used are instruction and testing. Instructional accommodations are changes to the delivery of classroom instruction or the accompanying materials. Instructional accommodations change how students learn but do not change what they learn. Testing accommodations are changes to the format of a test or its administration procedures. Testing accommodations change how students are tested but do not change what a test measures. IRIS Center at Vanderbilt University

Short for alternative text. A text caption, associated with an image or other element, that is rendered if the usual content cannot be rendered. ("Wiktionary" is licensed under CC BY-SA 3.0)

Assistive technology is any item, piece of equipment, software program, or product system that is used to increase, maintain, or improve the functional capabilities of persons with disabilities.Assistive technology helps people who have difficulty speaking, typing, writing, remembering, pointing, seeing, hearing, learning, walking, and many other things. Different disabilities require different assistive technologies. Examples include low-tech: communication boards made of cardboard or fuzzy felt, special-purpose computers, hardware: prosthetics, mounting systems, and positioning devices, special switches, keyboards, pointing devices, screen readers, communication programs, electronic devices, wheelchairs, educational software, power lifts, pencil holders, eye-gaze and head trackers. Assistive Technology Industry Association

The process by which a content user gives proper credit to the original creator of a work when a portion of that work is reused or adopted outside of its original context. Attribution typically includes a link to the original work and information about the author and license. ( Adapted from "Wikipedia" is licensed under CC BY-SA 3.0)

A method of designing an educational curriculum by setting goals before choosing instructional methods and forms of assessment. ("Wiktionary" is licensed under CC BY-SA 3.0)

Co-creation or co-designing is a learning process whereby knowledge consumption and knowledge creation are parallel processes. It is often realised in education by renewable assignments such as the creation of open textbooks by students. (Adapted from "A Guide to Making Open Textbooks with Students" by Rebus Community is licensed under CC BY 4.0). See also Renewable assessment.

A set of open licenses that allow creators to clearly mark how others can reuse their work through a set of four badge-like components: Attribution, Share-Alike, Non-Commercial, and No Derivatives.

Any impairment, or difference in physical, mental, intellectual, cognitive, learning, or communication ability. Disabilities can be permanent, temporary, or episodic (meaning that the impact of the disability can change over time). There are different types of disabilities, including physical, vision-related, hearing-related, and cognitive disabilities. The specifics of a disability vary by person and a person can have more than one disability.

An assessment task which has no utility after the student has completed it. ( Adapted from "What is Open Pedagogy?" by David Wiley is licensed under CC BY 3.0)

The quality of being diverse or different; difference or unlikeness. ("Wiktionary" is licensed under CC BY-SA 3.0)

Equality is when each individual or group of people is given the same resources or opportunities. Equity is when each individual or group of people is given resources or opportunities that account for imbalance in social systems. Equity aims for equal outcomes.

Design that considers the full range of human diversity with respect to ability, language, culture, gender, age and other forms of human difference.

The practice or policy of providing equal access to opportunities and resources for people who might otherwise be excluded or marginalized, such as those having physical or mental disabilities or belonging to other minority groups. A pedagogical practice that relates to both inclusive education and progressivist thinking is Universal Design for Learning (UDL). This method of teaching advocates for the removal of barriers in the physical and social environments that students of all abilities are within, as this is the main reason why students are unable to engage with the material presented in class. (Adapted from "Wikipedia" is licensed under CC BY-SA 3.0)

Teaching, learning, and research materials that are either (a) in the public domain or (b) licensed in a manner that provides everyone with free and perpetual permission to engage in the 5 R activities. (Source: "Open Education" by Creative Commons, is licensed under CC BY 4.0)

The set of teaching and learning practices that are only possible or practical in the context of the 5R permissions that are characteristic of OER. (Source: "International Review of Research in Open and Distributed Learning" by David Wiley and John Hilton, is licensed under CC BY 4.0)

Resources, tools and practices that employ a framework of open sharing . (Source: "About the Open Education Consortium" by Open Education Consortium is licensed under CC BY 4.0)

Practices which encourage the development of openness, community engagement, transparency, responsibility, sharing, and accountability in education. (Adapted from "Open Education Practices: A User Guide for Organisations/Resources and Practices" by Otago Polytechnic, Open Education Practices: A User Guide for Organisations and Individuals is licensed under CC BY-SA 4.0

Teaching, learning, and research materials that are either (a) in the public domain or (b) licensed in a manner that provides everyone with free and perpetual permission to engage in the 5 R activities. (Adapted from "CC Wiki" by Creative Commons is licensed under CC BY 4.0 )

A copyright licence which grants permission for all users to access, reuse, and redistribute a work with few or no restrictions.  ("The OER Starter Kit " by Abbey Elder is licensed under CC BY 4.0)

A set of pedagogical practices that include engaging students in content creation and making learning accessible to all.  ("The OER Starter Kit " by Abbey Elder is licensed under CC BY 4.0)

An openly licensed and free to access textbook; an OER meant to be used as a textbook for a course. ("The OER Starter Kit " by Abbey Elder is licensed under CC BY 4.0)

The process of perceiving or portraying someone or something as essentially alien or different ("Wiktionary" is licensed under CC BY-SA 3.0)

A  fictional user-type created to represent real people that might use your service, product, or site. Creating multiple and diverse personas can help you recognize different needs and expectations of potential users.

A work which is not covered under copyright law, whose copyright has expired, or which has been dedicated to the public domain by its rightsholder is said to be in the public domain. ("The OER Starter Kit " by Abbey Elder is licensed under CC BY 4.0)

Assessment tasks in which each student cohort creates or contributes to openly created work, developing an ongoing body of knowledge and which value outside the creators’ learning experience. (Adapted from "Wiley, D., & Hilton III, J. L. (2018). Defining OER-enabled pedagogy. International Review of Research in Open and Distance Learning, 19(4)." is licensed under CC BY 4.0)

An assignment task which forms part of renewable assessment. (Adapted from "Wiley, D., & Hilton III, J. L. (2018). Defining OER-enabled pedagogy. International Review of Research in Open and Distance Learning, 19(4)." is licensed under CC BY 4.0)

A process intended to design products that are usable by all people, with or without disabilities, to the greatest extent possible. (Adapted from "Wikipedia" is licensed under CC BY-SA 3.0)

UDL is a framework of learning and teaching based on neuroanatomy and functional neuroimaging research techniques. UDL resists a one-size-fits-all approach to education and posits instead that teachers, educators, and instructional materials should effectively respond to individual differences inherent within a learning environment. Across learning goals, methods, materials, and assessments, Universal Design for Learning encourages offering—

Multiple means of representation to give learners various ways of acquiring information and knowledge,
Multiple means of expression to provide learners alternatives for demonstrating what they know, and
Multiple means of engagement to tap into learners' interests, challenge them appropriately, and motivate them to learn.

Using UDL principles in a classroom removes obstacles to curriculum access and provides students with alternative methods to demonstrate what they know. It acknowledges that there is more than one way to learn and respects individual learning differences. CAST's About UDL

Web Content Accessibility Guidelines is developed with a goal of providing a single shared standard for web content accessibility that meets the needs of individuals, organizations, and governments internationally. The guidelines make web content more accessible, primarily for people with disabilities. The World Wide Web Consortium (W3C)/Web Accessibility Initiative (WAI)