Post History

How to get rid of the tag ordinals?

On my latest question, which was about ordinal numbers (often just called ordinals), I originally used the new tag ordinals. Later I noticed that ordinal-numbers would be a much better name for that tag. Since my question was still the only one using the tag, I simply retagged it, assuming that the now unused tag would eventually go away. 

Now I noticed that the tag is still there. Therefore my question:

How to get rid of the tag ordinals?