Should ZIP be always uppercased?

[Zoli]

Is it correct to write "Zip" with only the first letter uppercased? By "Zip" I mean ZIP code. It seems to be an acronym.

 

[SoothingDave]

It should be ZIP. It is an acronym. Zone Improvement Plan.

Most don't know that and it's become so generic of a term that you will see it capitalized or not.

 

[Aubree]

FWIW, the 2008 U.S. Government Printing Office style guide lists ZIP Code as its preferred capitalization. But the GPO does not dictate style for anyone outside the GPO, even other agencies of the federal government. AP and the HHS website, among others, call for all-caps ZIP but lowercase code.

 

[emsr2d2]

@Aubree What are "AP" and "HHS"?

Also, please don't use things like "FWIW". Learners won't be familiar with such abbreviations/acronyms. Always write phrases out in full, please.