So is it Addin or Add-in or Add in or, for that matter, plug-in?
This seems silly, arguing about the hyphenation of the word, but there has been an extensive debate on the “correct” spelling of the word. A debate which ultimately I lost – but I get the last word here: it is my blog.
The “official” Microsoft spelling of the word is “Add-in” with the hyphen. In code identifiers – namespaces, class names, etc. – we capitalize the “I” and remove the hyphen (which is of course illegal in most languages in identifiers): AddIn.
That is where the debate ended. However, in this forum I will almost exclusively use the spelling Addin. Why? It is my contention that Addin is the ultimate evolved form of the word. In English, compound words go through an evolutionary process. They begin life as two separate words used together: Add in, Run time, Base ball. Next they take on the hyphenated form as their use together becomes more common: Add-in, Run-time, Base-ball. And finally they achieve their closed form when the two words are regarded as a single work commonly: Addin, Runtime, Baseball. See this entry on compound words and their evolution in the The American Heritage® Book of English Usage : http://www.bartleby.com/64/84.html.
It is my contention that Addin has finally achieved its ultimate closed form and I intend to remain in the vanguard here. Technically all forms are “correct,” the question is which is most correct. As noted in the above citation, with most things in the English language “correctness” is dictated by usage. Here my debaters may have a leg up on me – this was certainly the prevailing argument – if one searches Google for citations of each spelling Add-in beats Addin about 2-1. It is my contention, though that the *new* citations will favor the more evolved form. The “Add-in” citations are simply legacy from the evolutionary process. The fact that there are as many Addin citations as there are, in my opinion, proves that the evolution has occurred and Add-in is going the way of the Base-ball.
The Univeristy of Minnesota style guidelines support me further, saying that current trends tend to eschew the hyphenated form altogether as archaic: http://www1.umn.edu/urelate/style/hyphens.html
So you say to-ma-to, I say tomato. Let’s call the whole thing off.
As for Plug-in, well, it is synonymous with Addin. Microsoft tends to favor the latter term. Some other companies tend to favor Plug-in. I am not going to go into Plugin vs. Plug-in. Microsoft also has things called “snap-ins.” These are, generally, a specific kind of addin. But that leads to another topic: What, precisely, is an Addin?
