There are three different uses I can think of:

* Tab key
* Tab character
* Tab UI element

While the Tab key usually generates the tab character, they should still be treated separately. If you're asking how to make the tab key insert a tab character, you're probably doing something wrong or need to read a `vi` tutorial.

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I suggest we do the following instead of simply merging:

* Search the *tab character* and *tab key* uses of `tab` and `tabs`, and retag them to `tab-key` and `tab-character` (or `tabulator-key`, if that's common in English? I'm not sure whether it helps or detracts...)
* Create a new tag `tabbed-interface` (or `tab-ui`?) and make both `tab` and `tabs` synonyms.
* Create tag wikis for these tags, clearly describing what each tag is for, maybe (not in the excerpt, but the actual wiki) linking to the other, similar but unrelated tags.

The reasons:

* The 3rd meaning is the most common, i.e. tabbed interface. Therefore this is the target of the synonyms `tab` and `tabs`.
* All tags start with `tab`, so users who type this will be presented all of these as options. `tab` and `tabs` will not be presented, as they're synonyms, so users will get the choice of three distinct options.