- What are tag synonyms?
- How can tag synonyms be distinguished from "real" tags?
- How are new tag synonyms created?
- Who can create tag synonyms?
- How can I delete/reverse/undo bad tag synonyms?
- What are merged tags?
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There's a lot of good info in the announcement of tag synonyms on the Stack Overflow blog.
What are tag synonyms?
A tag synonym is usually a tag that has exactly the same meaning as some other tag, such as algorithm and algorithms. In some cases, tags that are subsets of other tags will also be considered synonyms, such as java-se for java.
The system organizes tags in a master–synonym relationship. All uses of the synonym tag for any given master tag are automatically converted to the master tag. So, users can enter a synonym tag when writing a question, but the master tag will be displayed when the question is loaded. Editing a question tagged with a synonym tag causes it to be replaced by the master tag. Similarly, when users search for questions tagged with a synonym, a list of questions tagged with the master will be displayed.
A master list of synonyms is available at
How can tag synonyms be distinguished from “real” tags?
Tag synonyms are replaced by the respective master tag on almost every occasion, e.g., when you search for a tag, try to apply a tag to a question or follow a link to the tag.
Note that it is rarely necessary for a user to make this distinction.
How are new tag synonyms created? Who can create tag synonyms?
Suggestions will be automatically approved when they reach a score of four, and automatically deleted when they reach a score of negative two. If there aren’t enough people aware of the proposed tag synonym, or if you aren’t sure whether the synonym is a good idea, open a discussion on your site’s meta, tagged discussion tags tag-synonyms (for questions about the synonyms on this site, Meta Stack Exchange, add meta).
The synonym admin panel is located at
When a synonym is created, the synonymous tag is not removed from questions, but cannot be added to new questions anymore (the master tag will be chosen instead). Thus, the synonymisation can still be reverted comparably easily.
How can I delete/reverse/undo bad tag synonyms?
Only moderators can correct a bad synonym. Therefore the only recourse is to post a question on your meta site explaining the problem with the synonym relationship. Use the tags described as above. Give the community a few days to show support or make alternate proposals. Once the discussion has settled, a moderator will perform what correction is he or she deems necessary given the discussion. (You may retag your question feature-request once you think the correct course of action has been determined. If there is still no moderator response after a couple of days, contact a moderator in chat.)
What are merged tags?
All good tag synonyms should eventually be merged (source). This retags all questions tagged with a synonym – which is not automatically done when a synonym is created. As merging is not (easily) reversible, it should be done with caution and only when a synonym is established. Only moderators can perform a merge.