While typing a post on SO, I noticed that the word "ok" (when used in the sentence "I'm still learning so it is ok") was marked as misspelled (got to love spellcheck!) The first suggestion, however, confused me. The suggestion was "OK" (as opposed to "ok"). Then I thought, what about "okay"?
So, why is "OK" correctly spelled (vs "ok") and what is their relationship to the word "okay"? They all have the same meaning; could "OK" be a form of slang or abbreviation?
"Okay" is listed as a variant spelling of "OK" in my local dictionary. This previous answer has a good description on the origin of "OK":
According to the OED, it's an initialism of oll (or orl) korrect, first seen in 1839.
I suspect that "ok" is not listed as an acceptable spelling because the origin of the word was "OK" due to its being an initialism. The variant of "okay" is just how one would spell a word with the same pronunciation. With "OK" and "okay", there isn't much need for "ok".
O.K. was probably the first spelling (and there are dozens of theories about its origin). OK is an obvious shortening, maybe by somebody who had only heard the phrase. But ok would be something different, perhaps a small okapi. That's what your spellchecker thought wasn't okay.
Edit: O.K. is pronounced 'okay', and so is OK. But ok would be pronounced 'ock'.
From AP Style...
Home > AP Stylebook > Chapter O > OK, OK’d, OK’ing, OKs OK, OK’d, OK’ing, OKs Do not use okay.
http://www.apstylebook.com/online/?do=entry&id=2112&src=AE
From Grammar Girl:
The Origin of OK "OK" was born in America in the 1830s. Much like the text messaging abbreviations of today, "OK" was an abbreviation for a funny misspelling of "all correct": "oll korrekt." According to the Oxford English Dictionary, the "okay" spelling didn’t appear until 1895.
There were other odd abbreviations with similar origins in the same era ("OW" for "oll wright," for example), but Martin Van Buren, whose nickname was Old Kinderhooks because he was born in Kinderhook, NY, adopted the motto "Vote for OK" and called his supporters the "OK Club" in his presidential campaign, and the campaign publicity established "OK" in the American lexicon.
"OK" and "Okay" Are Both OK The two spellings peacefully coexist today: the Associate Press recommends "OK" and the Chicago Manual of Style recommends "okay." My publisher follows Chicago style for my books, but to honor the word's origins, I insist on "OK" instead of "okay." So far, they have been kind enough to indulge me.
I will try here to present how the “O.K” initials; was first finds in English Language.
When the first Greek emigrants came to the American continent they have no any knowledge in English.
They only want to work and nothing additional knowledge wants to have.
An exception to this were few of them have the willing start learning English, so there Bosses assign to them a leading roll in smaller groups.
Under these circumstances these individuals has the task to cover the gap between the Greek with no English knowledge and there Bosses.
So every time when a job was finished they write on document’s the sign of “O.K” which means “Olla” “Kalla” which translated in English is “Everything is good”.
So all they’re happy because they’ve found a common area of communication between them by typing the initials “O.K”.
So the echo of the initials "O.K" is "Okay" because of speling the two letters.
I'd say nothing explains better than examples. Found some good ones here. They've quoted news publications to give a better understanding. One thing is a sure-shot: There is nothing called "ok"... It's either okay or OK or O.K....
Simply because you spelled "ok" in small letters.
In correct spelling/ grammar, the word should be capitalized "OK". I've experienced this problem myself. "Okay" is just another way of spelling the word, which is OK to use. There are also other forms of the same word like "O.K" or "O.K." and those are also acceptable, but are used rarely in everyday life. So feel free to write "OK", "Okay" or "O.K" since all of them are correct.
The correct answer is "okay" is an African Wolof word which entered American English during the slavery era.
The large number of joke "backronyms" for "okay", such as the Old Kinderhook Club, or the OK Brand & Coral, represent literate Americans, in the 1800s, absorbing this word without acknowledging its source.
(Unfortunately, the large number of joke backronyms permit dictionaries to pick any number of non-African word origins. "Banana" does not have this problem, because it does not happen to match any English letter names...)
As an historical footnote, the ancient Greek signal flags for "all is well", "Ola Kala", appeared as "OK." This is entirely a coincidence, because Greeks did not pronounce "OK" like "okay."
I think okay is used in narrative prose and sentences e.g "Father okayed admission of his son to local sports club". Whereas O.K. is more often used in conversational sense E.g a boss says: "you will go to the warehouse tomorrow and purchase these items." The employee says: "O.K. I will do it. But shall I pay as COD or ask them to charge to account?"
Okay is the spelling used in prose. O.K. is only used in prose if the writer is describing the activity of another writer. E.g.: "He wrote 'O.K.' on the invoice."
The most historically accurate spelling is the common 19th century one, Okeh, which was disfavored to disguise the native American origins of the term. See here: http://www.illinoisprairie.info/chocokeh.htm . The pronunciation of "Okeh" is "okay", so the spelling "okay" is more phonetically accurate, and might be preferred on those grounds.
The acronym "OK" is a made-up thing partly to support frontiersman Andrew Jackson and his running mate Martin Van Buren, and it was given a bunch of false acronym associations. The term was never an acronym, but it sounds like one. 19th century people, and many 20th century ones, knew it was frontier Choctaw.
So you use OK if you want to pretend its an acronym, and okay if you don't want to do that. I personally think the correct spelling one should use is the clearly native American okeh, but, to my shame, I always use "Ok" (one capital), since "OK" sounds like shouting, and either "okay" or "okeh" take two keystrokes longer to type.
