This question uses the [tag:adb] tag as an example, but it applies to any acronym tag that doesn't have a universal and common usage (like, say, pdf).  

[tag:adb] is a new tag.  I drafted a wiki and excerpt for it based on the usage so far (which refers to Android Debug Bridge).  As DavidPostill points out in a comment, adb already has multiple computer-related uses (also Advanced Debugger), so an acronym tag is just asking for misuse.  

Based on adb already referring to multiple things, the logical approach is to have spelled-out tags for each use and an adb tag that advises users to pick the appropriate one.

 - I can create a new [tag:android-debug-bridge] tag, move the [tag:adb] wiki contents to it, and retag the couple of existing questions.
 - We don't yet have any questions about Advanced Debugger, so we can't create a tag for that.
 - Rather than synonomizing [tag:adb] with a specific use, it should be turned into a "do not use" tag that guides readers to the appropriate choices.  Right now, there's only one choice, so this would imply editing the wiki excerpt as other adb-related tags are created.
 - As Ben N points out in his answer, more users think in terms of "adb" than "Android Debug Bridge", so simply deleting the adb tag may complicate tagging for users.
 - I'm not aware of a way to link a tag to more than one other tag to preserve it, and I don't think synonomizing allows you to have a different wiki.  It would also automatically link new question with the synonomized tag, which might be the wrong one.

**What's the best general solution for acronym tags, especially when they are known, or likely, to refer to multiple things?**

 - One thought: incorporate the acronym into the spelled-out tag. I don't know the limits on tag text (max characters, number of hyphenated terms, acceptable non-letter characters other than hyphen and I think period).  

   If each spelled out tag includes "adb", something like: [tag:android-debug-bridge-adb], they could potentially show up for selection when the user enters adb (as long as there aren't too many tags that contain that letter combination; currently there are 6 in addition to [tag:adb], and I believe the displayed subset is based on popularity).

 - Other ideas?