Embargo periods on scientific research are now fairly commonplace. They are sanctions imposed by publishers on different versions of a research manuscript, often termed the author-accepted manuscript (AAM) or post-print, in order to delay public release of those versions. Typically at this stage, the publishers themselves have had little or no input to the process besides managing the peer review process through volunteer editorial staff.
These impositions now typically exist in the form of embargo policies, in which publishers ‘allow’ researchers to deposit these earlier versions (still peer reviewed) in a public repository of some sort, but with a delay of anywhere between 6-24 months, typically. This is commonly referred to as ‘green open access’, although the original definition of this simply required public archiving in a repository without any mention of embargo periods.