The acronym "SP" is first written in the document as: "contained in widely used or long-standing special permits (SP)."

Next it appears in the singular: "eliminate the need for numerous SP renewal requests."

Later it appears again in the plural form as: "submitted by the regulated community related to certain SPs and..."

Is this the correct usage for all three instances?

2 Answers 2


It seems that the author meant for SP to represent "special permit" not "special permits." Given this, the second and third are clearly correct.

As for the first, perhaps it could have been "long-standing special permits (SPs)," but that might imply that the abbreviation always included a lower-case s, similar to PhD, or IPsec.

A better approach might be to rephrase the sentence so that the first abbreviation, denoted in parenthesis, didn't represent a plural form.

  • If I use your suggestion to rephrase the sentence, then I could use "SPs" for plurar use in future usage, correct? Commented Feb 14, 2019 at 17:45
  • That's correct, @BrettA. I think some style guides may prefer "SP's" but I may be misremembering. The New York Times and the Chicago Manual of Style use apostrophes only when the abbreviation has periods. So it's "M.D.'s" and "M.R.I.'s" but "TVs", "CDs", "DVDs" and so forth. "FAQ on Style"
    – Juhasz
    Commented Feb 14, 2019 at 17:56
  • I'm going to fix it in the following way: "contained in certain widely used or long-standing special permits (SPs) that have an established safety record. The proposed revisions will provide greater regulatory flexibility and eliminate the need for numerous special permit (SP) renewal requests, ..." Any thoughts? Commented Feb 14, 2019 at 18:04
  • I and the other editors at work considered this question last year. One example (we work in a military office) was "weapons of mass destruction (WMD)"; does that indicate that "WMD" is plural and you can't later write about "a WMD"? We settled on the U.S. Government Publishing Office style, and this is what we put in our own style guide: When initials are being given for a plural or possessive form, "a lowercase s is included within the parentheses. For example, 'sport utility vehicle (SUV),' 'sport utility vehicles (SUVs),' and 'sport utility vehicle’s (SUV’s).'”
    – Literalman
    Commented Feb 15, 2019 at 15:33
  • @BrettA, I don't think it necessarily needs to be fixed. I didn't find the original confusing. On the other hand, pluralizing the abbreviation the first time it appears also seems fine. Yes, there's a chance that someone reading "SPs" might think it stands for special psychology or something, but they would probably figure out that it was plural when they read "SP" in a similar context. If I were reading a paper that included "special permits (SPs)...special permit (SP)" I would probably think that the editor had forgotten that SP had already been defined. Which, again, is no great crime
    – Juhasz
    Commented Feb 15, 2019 at 15:40

@BrettQ, no I wouldn't put "SP" in parentheses twice in different forms, I would just make the first use of the initials match the grammatical use where they appear, in this case "SPs."

  • So you would write (SPs) first, and then you would "automate" future singular use by writing SP, and assume the reader will understand? Commented Feb 19, 2019 at 15:46
  • Yes, if "SPs" means "special permits," then "SP" means "special permit," singular. That's the Government Publishing Office rule I would follow.
    – Literalman
    Commented Feb 19, 2019 at 16:21

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