Open Access: scholarly literature that is free to read and often has various re-use rights
Article Processing Charge (APC): A fee charged to the author, institution, or funder to cover the cost of an article. This fee is in lieu of charging subscriptions to read the article.
Hybrid Journal: A type of journal in which some articles are published Open Access and others articles or not. Hybrid journals are typically longstanding journals that provide an Open Access option, and charge subscription fees.
Toll access journal: A journal that requires payment to access the scholarly content
Green OA publishing refers to the self-archiving of published or pre-publication works for free public use. Authors provide access to preprints or post-prints (with publisher permission) in an institutional or disciplinary archive such as eCommons@Cornell and arXiv.org.
Gold OA publishing refers to works published in an open access journal and accessed via the journal or publisher's website. Examples of Gold OA include PLOS (Public Library of Science) and BioMed Central.
Hybrid journals offer authors the option of making their articles open access, for a fee. Hybrid journals are still fundamentally subscription journals with an open access option for individual articles. They are not true open access journals, despite publishers' use of the term "gold open access" to describe this arrangement, and the Cornell Open-Access Publication Fund does not support open access fees to hybrid journals.
PLOS Journals 215,000+ peer-reviewed articles are free to access, reuse and redistribute