## Which one is correct: Id or ID?

5

I find the people using both:

"Id" and "ID"

I do not know which one is correct.

To me, the 1st one ("Id") is correct, as "Id" and "ID" are abbreviations of "identifier". The correct one is "Id". "ID" appears to be an acronym of two words, though there is only one word, "identifier".

Can anyone please shed some light on the issue?

Question was closed 2016-02-06T21:26:40.273

ID can be a shortened form of other words/phrases besides identifier. For example, "ID" can be a shortened form of identification card (e.g., "May I see an ID, please?"), or even the verb identify (as in, "The victim was able to ID the robbery suspect"). – J.R. – 2016-02-06T18:24:09.517

I imagine lots of people capitalize both letters because id is a word in its own right, and in many fonts, the lower-case version of L is identical (or easily confused with) the upper-case version of i. It's such a short abbreviation it's not going to seriously distract the reader if it's written entirely in upper case, and it's important to note that in many/most contexts it's actually pronounced as "eye-dee", so it just seems natural to write it as if it's two letters. The question "Which one is correct?" is practically impossible to answer. – FumbleFingers Reinstate Monica – 2016-02-06T18:25:42.867

1Is your context ordinary writing, where it is OK to have abbreviations that consist of multiple capital letters in a row? Or is your context computer programming, where camelCaseIdentifiers and CapitalizedCamelCaseIdentifiers are common? – Jasper – 2016-02-06T18:37:58.300

*Definitions of id* Looks like ID wins. I have never seen it written differently. (AmE) – user3169 – 2016-02-06T19:54:55.830

@Jasper: I don't think ELL would be interested in this question at all if the OP were simply concerned with the computer programming context, camelCaseIdentifiers, etc. – FumbleFingers Reinstate Monica – 2016-02-06T21:19:03.930

@Fumble - I think we all agree with that, but I think Jasper's comment is trying to figure out where the OP might have seen Id to mean "identifier." It seems like a plausible guess. – J.R. – 2016-02-06T21:56:19.803

@FumbleFingers - I am not a computer programmer; nor this is a computer programming site. I am an English learner. I have seen it being used differently, such as 'Mention your email ID' and 'Mention your email id'. This triggered the enquiry. Hence, I posted this question. I hope the context is now clear and you will not adjudge the question as "off-topic". – Kirti – 2016-02-07T10:16:22.640

@Jasper - I am not a computer programmer; nor this is a computer programming site. I am an English learner. I have seen it being used differently, such as 'Mention your email ID' and 'Mention your email id'. This triggered the enquiry. Hence, I posted this question. I hope the context is now clear and you will not adjudge the question as "off-topic". – Kirti – 2016-02-07T10:18:51.307

@Kirti: I'm a little surprised your question has been closed. I've voted to reopen, but that will only happen if 4 other users do the same. Having looked into it a bit more closely, I've discovered / been reminded of a couple more relevant points. OED's first recorded use is 1955 (so references to ID papers in a WW2 movie are anachronistic). That's in an "abbreviations dictionary", where it's given as Id. Their third citation (New Statesman, 1965) is ID's’..are pretty obscure to English readers as translations of 'papiers' (identity documents). – FumbleFingers Reinstate Monica – 2016-02-07T13:08:15.940

...in short, although neither the full subscription-only OED nor any online dictionary I can easily find explicitly points it out in the definition itself, that 3rd citation above clarifies that originally it was a "proper" abbreviation of two separate words (it's not just the first two letters of *identity*). But not realizing that myself, I spent several fruitless minutes trawling the Net to see if there were any other common 2-letter "abbreviated" forms of a single word where both letters are capitalized. Unsurprisingly, perhaps, I didn't find any (and ID isn't one of them! :) – FumbleFingers Reinstate Monica – 2016-02-07T13:14:14.463

...actually, I have now found one! Apparently, the abbreviation SS (both capitalized) stands for (plural) Saints. – FumbleFingers Reinstate Monica – 2016-02-07T13:16:48.767

1@FumbleFingers - Let me agree that "ID" is short form of "Identity Document". But, we find a commonplace thing, such as, "What is your email ID" or "What is your email id". Obviously, the speaker is asking for "email Identity" or "email Identifier" and not for "email Identity Document" or email Identity Card". To me, "id" or "ID" is short form of "Identity" or "identifier". But, I am not sure. One more thing, this is not a general reference. I did not find this in Collins dictionary (Indian Reprint 1991) I use. That is why, I posted this question. But, I am surprised that it is "on hold". – Kirti – 2016-02-07T17:57:22.403

@user3169 - Abbreviation too follows a rule. I do not know what rule "ID" follows. In "ID", as both letters are in capital form, it appears that there are two separate words, first commencing with "I" and the second with "D". Even after putting in several hours of thought, I am just unable to figure out what those two words could be in "email ID". The question of OP appears difficult to answer, though "ID" and "id" are common abbreviations nowadays. – Dinesh Kumar Garg – 2016-02-07T18:29:42.520

Kirti: I realize not everyone would necessarily agree with me, but personally I don't find email ID an acceptable usage. It's fine to talk about a user ID - your identity expressed as a *user name* in the context of a computer system. But I can't make sense of "your identity as an email" - that's your email *address*, which doesn't feel like an "ID" to me, – FumbleFingers Reinstate Monica – 2016-02-08T13:40:32.613

@FumbleFingers - Sir, you are correct. Logic says it should not be "email identity" or "email identifier"; it should be rather "email address". But, I find a lot of examples when people use "email Id" or "email ID". Honestly, I have never found any person writing "email address" instead. Then, how should we construe "email Id" and email ID"? Should we construe them as meaning "email Identity" or "email Identifier"? – Dinesh Kumar Garg – 2016-02-11T09:26:31.660

@Dinesh: I think we should just accept that "ID" is now a "word" in its own right - for which both "identity" and "identifier" could serve as synonyms, but in practice the real meaning of the short form invariably implies *unique identity / identifier*. – FumbleFingers Reinstate Monica – 2016-02-11T13:30:19.317

@FumbleFingers - Sir, agreed. If "ID" is a word in own right, then it is only the first letter of the word "ID" which should be in capital; the word should then be "Id" (and not "ID"). Next, what do you mean, sir, when you say "...real meaning of short form ...unique identity / identifier"? Do you say that "ID" is a short form of some word (and not itself a word in its own right). – Dinesh Kumar Garg – 2016-02-20T06:22:23.010

@Dinesh: What I said was that in principle ID was originally an "initialism" for Identity Documents. But that's pretty irrelevant, since most native speakers aren't consciously aware of this (that's why we'll happily refer to ID papers, ID documents, etc.). – FumbleFingers Reinstate Monica – 2016-02-20T15:07:47.890

... In practice today it's just "a word" - and you've only to check the relevant NGram to see that both letters are almost always capitalized. So anyone claiming that neither (or only the first letter) should be capitalized is simply wasting his time. The established usage is never going to change.

– FumbleFingers Reinstate Monica – 2016-02-20T15:09:49.367

@FumbleFinger - Thank you. The last comment that you made clears the whole thing. Thank you very much once again. One thing: just see the discussion that this question has elicited. Still, the question has been termed "off-topic". This is really unfortunate. Can you please take up the issue at the appropriate level so that the question is no longer "off-topic". – Kirti – 2016-02-20T15:31:49.767

@Kirti: I already voted to reopen (and commented above that I'd done so), but there weren't 4 other users voting to support that position. I could raise a question on ELL meta asking for people to reconsider, but I'm not a mod here, and I probably have no more influence than any other user when it comes to On/Off Topic differences of opinion. What I suggest is that since it's your question, ideally *you* should raise a "Please re-open" post on meta (which I will support, obviously).

– FumbleFingers Reinstate Monica – 2016-02-20T16:11:41.313