Accessibility - having a place, environment, or event that is set up to be barrier free for all individuals to access (https://youth.gov/youth-topics/inclusion-and-accessibility)
Accessible - easily used or accessed by people with or without disabilities (https://www.merriam-webster.com/dictionary/accessibility)
Accessible Design - a design process in which the needs of people with disabilities are specifically considered (https://www.washington.edu/accesscomputing/what-difference-between-accessible-usable-and-universal-design)
Universal Design - the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design (https://www.washington.edu/accesscomputing/what-difference-between-accessible-usable-and-universal-design)
Usable Design - a design process in which products that are created are easy and efficient to use (https://www.washington.edu/accesscomputing/what-difference-between-accessible-usable-and-universal-design)
Open internet websites for further research:
The following contains the shared document for the development of the Social Media Policy Toolkit, a shared service of the Federal Social Media Community of Practice lead by teams including The Department of Labor’s Office of Disability Employment Policy.
Usability.gov is the leading resource for user experience (UX) best practices and guidelines, serving practitioners and students in the government and private sectors. The site provides overviews of the user-centered design process and various UX disciplines. It also covers the related information on methodology and tools for making digital content more usable and useful.
This document presents the accessibility requirements users with disabilities have with respect to audio and video on the web. It first provides an introduction to the needs of users with disabilities in relation to audio and video.
We have web accessibility in mind: Expanding the potential of the web for people with disabilities by empowering individuals and organizations to create accessible content.
Accessible America by 
Creating Accessible Online Instruction Using Universal Design Principles by 
Developing a Library Accessibility Plan by 
Beyond Accessibility Compliance by 
Designing Accessible Learning Content by Links to e-books & articles:
SUNY Adirondack Accessibility Services
The Accessibilities Services Office provides equal educational opportunities to students with disabilities by ensuring full access to all programs, activities and facilities of the college. The Accessibility Services Office strives to maintain the quality and integrity of SUNY Adirondack’s academic standards and programs while providing accommodations in compliance with the Americans with Disabilities Act of 1990 and section 504 of the Rehabilitation Act of 1973.
Professional staff within the student disability services offices work in partnership with students to provide accommodations for participation in living and learning at SUNY. Students are advised to connect with the campus coordinator at the respective campus to determine how a specific need can be met, in and out of the classroom.