Green Open Access – author or institution can archive peer-reviewed articles in openly accessible digital repositories.
Gold Open Access – author or institution pay a fee to make peer-reviewed articles available to all on journal publisher web sites.
Preprint (Pre-Print) – an article that has been written and submitted to a scholarly journal that has not been peer-reviewed.
Postprint (Post-print) - an article that has been written and submitted to a scholarly journal that has been peer-reviewed. It is not the final version which is published by the journal.
Version of Record – the official final version of a scholarly article that has been peer reviewed and published in a journal.
More definitions related to open access and scholarly communication can be found on the University of Illinois Libraries' Scholarly Communication Glossary and the SHERPA Glossary of Open Access Abbreviations, Acronyms and Terms.