Is IOU an abbreviation, an acronym, or an initialism?

Question

IOU stands for I owe you and we pronounce each letter separately. But how do we classify that construction"?

• abbreviation: a shortened form of a word or phrase
• acronym: an abbreviation formed from the initial letters of other words and pronounced as a word
• Initialism: an abbreviation consisting of initial letters pronounced separately
• back-formation: a word that is formed from an existing word which looks as though it is a derivative, typically by removal of a suffix

^{All definitions provided by Oxford Dictionaries Online}

It can't be an abbreviation because there is no shortening, clipping or back-formation. Take for example phone which is an abbreviation of telephone, or edit which is a back-formation of editorship and editor. I would argue that abbreviations are words that have been shortened, a faster way of writing or saying something. Another example would be Prof for professor.

It can't be an acronym because we don't pronounce IOU as one word, whereas we do with NATO and RAM.

It can't be an initialism because if it was, it should be written as IOY (I Owe You)

Other examples that spring to mind is CU for see you and YRU for why are you, where initialism would dictate that the proper forms be SY and WAY.

How do linguists define this structure? Is there a more specific term than abbreviation?

Answer 1

It could be characterized as a rebus

a riddle or puzzle made up of letters, pictures, or symbols whose names sound like the parts or syllables of a word or phrase [Merriam-Webster]

While a rebus often contains images, letters being used to represent syllables is common.

[Wikipedia]

In particular, the Encyclopaedia Britannica states

Literary rebuses use letters, numbers, musical notes, or specially placed words to make sentences. Complex rebuses combine pictures and letters. Rebuses may convey direct meanings, especially to inform or instruct illiterate people; or they may deliberately conceal meanings, to inform only the initiated or to puzzle and amuse.

....

A familiar English rebus is the debtor’s “IOU,” for “I owe you.”

If you wanted to be more precise in defining it, you could say alphabetic rebus.

Answer 2

I think it is a phonetic abbreviation in the sense that IOU represents the (phonetics) sound of “I Owe You”, not its proper initials, similar to CU for “see you”. (From The American Heritage® Dictionary of the English Language)

• The act or product of shortening.
• A shortened form of a word or phrase used chiefly in writing to represent the complete form, such as Mass. for Massachusetts or USMC for United States Marine Corps.

IOU: (from Investopedia)

• An informal document that acknowledges a debt owed. IOU is an abbreviation, in phonetic terms, of "I owe you".

Answer 3

It is a gramogram or grammagram. https://en.wikipedia.org/wiki/Gramogram#Examples_of_sentences

A gramogram or grammagram or letteral word is a letter or group of letters which can be pronounced to form one or more words, as in "CU" for "See you". They are a subset of rebuses, and are commonly used as abbreviations.

Answer 4

Initialism: an abbreviation consisting of the first letter or letters of words in a phrase, syllables or components of a word, or a combination of words and syllables and pronounced by spelling out the letters one by one rather than as a solid word. - AHDEL

There is also alphabetism (Farlex Trivia Dictionary): The expression of spoken sounds by an alphabet; the representation of the sounds of speech in consistent graphic form.

Initialisms (sometimes called alphabetisms) are formed from the initial letters of a string of words and are pronounced as a sequence of letters, e.g. BYOB, USA, DVD. Acronyms are formed from the initial letters or parts of words in a sequence, but have the distinction of being pronounceable words, e.g. RADAR, SCUBA.

Glottopedia defines alphabetisms as follows: an abbreviation that takes the first letter of each word of the base expression (like an acronym), and is pronounced by spelling out each letter.

But MW defines it as the use of letters as symbols; the representation of speech sounds by vowel and consonantal rather than syllabic signs. (IOU seems to fit that bill.)

Mindmap has subctegories of acronyms which are interesting to consider, including bacronym: refers to a word which seems like an acronym, but actually isn't, and states the difference between an acronym and an initialism is that an acronym forms a new word, while an initalism does not; you say "U.K." is an intialism for United Kindom: the periods are a dead-giveaway that's it's an intialism (but it's not an authoritative source).

Wikipedia, citing Homeland Security, calls it a pseudo-acronym, but the cited article doesn't list IOU.

I think it's a homoiousia of an alphabetism.