In academic publishing, an embargo is a period during which access is not allowed to certain types of users. The purpose of this is to protect the revenue of the publisher. Academic publishing describes the subfield of publishing which distributes academic research and scholarship. ...

Various types exist:

• a moving wall is a fixed period of months or years,
• a fixed date is a particular time point that does not change.
• a current year (or other period) is setting a time point on Jan. 1 of the current year, so that all material earlier than that is available. Though fixed during the year, it will change each year.

There are various purposes: It has been suggested that this article or section be merged into Embargo (academic publishing). ...

• In Delayed open access, the embargo separates the most recent period, for which a subscription is needed, from an older period, where a subscription is not needed and anyone may access the article. This is usually between 2 months and 5 years.
• In full-text databases, such as Ebsco or Proquest, it separates the most recent period, where only a title or abstract is available, from an older one, which is openly accessible. It also separates the relatively recent period for which sometimes only a low-quality copy, such as ASCII is available, from an older one, which may have higher quality versions, such as PDF.