The word “re” is not an abbreviation.
Nor is it an acronym or an initialization. It is simply a Latin word. Originally, it was almost invariably used in the phrase “in re,” meaning “in regard to.” From Wikipedia:
In re, Latin for "in the matter [of]", is a legal term used to indicate that a judicial proceeding may not have formally designated adverse parties or is otherwise uncontested. The term is commonly used in case citations of probate proceedings, for example, In re Marriage Cases; it is also used in juvenile courts, as, for instance, In re Gault.
For hints on the usages of a word, it can be handy to consult a thesaurus. From define.com:
From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:
31 Moby Thesaurus words for "re": about, anent, apropos of, as, as for, as regards, as respects, as to, concerning, in connection with, in point of, in re, in reference to, in regard to, in relation to, in relation with, in respect to, of, on, pertaining to, pertinent to, referring to, regarding, relating to, relative to, respecting, speaking of, touching, upon, with regard to, with respect to
Notice that in none of the usages shown is there a colon after re.
With the surge in microblogging sites such as Twitter, and their requirement for brevity, it is becoming increasingly common to see things like this:
I need to read up re: my city.
Or even worse, like this:
I need to read up RE: my city.
If you would do this, then you should also do this:
I need food, shelter, etc: in order to survive.
Only use a colon after “re” if the sentence structure requires it.
If you would use a colon there if the word were “regarding,” then go ahead and use it, but in the middle of a sentence, where there is no grammatical construction requiring it, leave it out!
I need to read up re my city.
You’re trying to save characters, right?
