The accepted version of a paper following peer review and with revisions made, but without copy-editing or formatting contributed by the publisher.
Some publishers allow the authors accepted version of a work to be made available after an ‘embargo period’. This is a period of time before which, a work that has been deposited into an institutional repository can be made open access. Embargo periods can vary from 6 to 36 months, with 12 months being the most common in Science & Health Disciplines and 18-24 months in Social Sciences & Humanities.
An offprint is a separate printing of a work that originally appeared as part of a larger publication, usually one of composite authorship such as an academic journal, magazine, or edited book. Wikipedia
Offprints are used by authors to promote their work and ensure a wider dissemination and longer life than might have been achieved through the original publication alone … historically, the exchange of offprints has been a method of correspondence between scholars.
Some publishers actively support scholarly sharing of offprints in order to promote published articles, e.g.
In academic publishing, a preprint is a version of a scholarly or scientific paper that precedes publication in a peer-reviewed scholarly or scientific journal. The preprint may persist, often as a non-typeset version available free, after a paper is published in a journal. Wikipedia
The key to the definition of “preprint” is in the prefix “pre”. A preprint is the author’s original manuscript, before it has been formally published in a journal. One of the primary purposes of preprints is that they allow authors to collect feedback on their work and improve it before submitting it for formal peer review and publication. Prints are often made available by a discipline specific repository or archive, such as arXiv