Edited Version of Question:

When a tag synonym is approved, the old tag becomes defunct. Unfortunately, it becomes harder to find questions that are tagged with the now-defunct tag. This seems to me to be the opposite of the point of tag synonyms (at least with respect to existing questions, although obviously not for future ones). It seems to me that there are a couple of possible solutions here (in ascending order of utility, according to my opinion, albeit probably descending order of preference for SE programmers):

  1. Clicking [searching] on a tag would only search that exact tag (e.g., the synonym), not a related one (e.g., the master).
  2. Clicking [searching] on a tag would search all tags that are connected to each other, including the master and all synonyms.
  3. When a tag synonym is approved, all questions tagged with the old tag are retroactively (and silently) retagged with the master, in more or less the same way that it happens when someone attempts to tag a new question with the defunct tag.

Original Version of Question:

Original title: Should we retag questions that have a now-defunct tag with the synonym?

Since I seem to be stirring the hornets' nest anyway...

If a tag synonym is approved, the old tag becomes defunct and questions tagged with it may become harder to find. Retagging dozens of questions at once seems like a bad idea. However, from time to time, people will come across a question tagged with the old tag. In such a situation, is it appropriate to change the tag from the defunct one to the approved master tag? (That is, even though you are not making any substantive edits.)

  • 1
    Have you actually tested your assumption about "defunct" tags becoming "harder to find"? E.g., tree (one occurrence) has been replaced by cart (69 occurrences) as a synonym. Guess what happens when you search on the tree tag? :-)
    – whuber
    Commented Jun 7, 2012 at 19:36
  • 1
    @whuber, are you getting a different result than I am? I can't find the question tagged tree. Commented Jun 7, 2012 at 19:45
  • 2
    That's the entire point, gung: there are few or no questions with the "tree" tag. But because tree is a synonym of cart, a search for "[tree]" turns up all the questions tagged "cart". That makes tree easier to find, IMHO.
    – whuber
    Commented Jun 7, 2012 at 19:49
  • @whuber, maybe I'm missing something here (it wouldn't be the first time). But consider the following: here is one of my (evidently 8) answers to questions tagged logistic-regression; however, if you search on the LR tag on my profile you get this. Notice that that question is not listed in the search output. (As a result of these facts, it took me a long time to find an example for you.) Commented Jun 7, 2012 at 21:04
  • Thus, the question is, should I, eg, retag that question as logistic so that it would become more easily findable? Commented Jun 7, 2012 at 21:05
  • 2
    That sounds like search + synonyms is not working as it should, Gung. I don't like the idea of manually retagging ten thousand questions to cope with search limitations. Maybe you should recast this question to focus on that behavior (and perhaps tag it with bug).
    – whuber
    Commented Jun 7, 2012 at 21:23
  • @whuber, I wouldn't want to spend my time retagging them all either. I've changed the question, but appended the original below it; I can delete the old question entirely if you think that's best. Commented Jun 7, 2012 at 21:53
  • 2
    @whuber, this doesn't seem to be getting much attention. Should we migrate it up to the big meta? Commented Jun 11, 2012 at 1:02

2 Answers 2


In most cases only one tag should be used for all questions after a synonym is created. All synonyms should point to this canonical tag, and all questions should be retagged to the canonical tag.

Fortunately, moderators have a tool to merge tags, so you don't have to do that by hand. Just notify a moderator on your site and remind them which tags should be merged and they can do that.

  • We have had many tag synonyms approved, but the old tags (ie the synonyms) don't automatically become the new tags (the masters) on the existing questions. You're saying that there's a trick to get this to happen automatically? Commented Jun 11, 2012 at 13:47
  • 1
    No, not automatically as merging tags isn't something that can be undone easily. Moderators have a tool to merge tags, but they have to start it manually, it's not automatically done when a synonym is created. Commented Jun 11, 2012 at 13:49
  • 4
    Yes, the mod interface offers the option to merge tag synonyms. This is an irreversible step, though. As a mod, I am reluctant to make merges solely to work around a "feature" of the search system. Searching ought to recognize tag synonyms
    – whuber
    Commented Jun 11, 2012 at 17:11
  • I will add that in the past, as a mod, I've definitely had trouble figuring out how to find only questions that have the "defunct" tag (rather than the primary tag it has been synonymized into). If part of the reason that tag synonyms don't automatically cause the tags to be merged is to ensure that only good tag synonyms are merged, then it needs to be easier to actually see which questions have which tag (rather than the tag listing aggregating questions with the tag + all of its synonyms together, with no way to separate them).
    – V2Blast
    Commented Sep 30, 2022 at 18:19

If you use SEDE, the data there contains the actual tags. So if you want to search specifically for the synonymized tag (and not the master tag), this would be a possible workaround.

Some examples from this site:

Of course, if the mods merge the above tags in the future, the examples I used to illustrate this will return no questions.

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