I think that Donald Trump has invented a new use for quotation marks. In several now-famous tweets, the president accused Barack Obama of wiretapping him during the election. Trump used quotation marks around versions of the word but also used the word without quotes.

When the accusation was criticized from many quarters, Trump, and those speaking for him, said that when the president said "wiretapping", he really meant "surveillance." On "Tucker Carlson Tonight," Trump emphasized that "wiretap" was in quotation marks. That was "important," he said, and something being overlooked by his critics and the press.

"And don't forget," Trump told Carlson, "I say 'wiretapping,' those words were in quotes. That really covers — because wiretapping is pretty old-fashioned stuff — but that really covers surveillance and many other things. And nobody ever talks about the fact that it was in quotes, but that's a very important thing."

As someone who wrote a chapter about quotation marks in the book "The Glamour of Grammar," I zeroed in on Trump's distinction. I lack the knowledge or the resources to conclude here that his usage is somehow improper or unprecedented. But it is, by all sources I have consulted, unconventional.

We have heard from a variety of commentators that Trump’s words should not always be taken literally — that he often speaks off-the-cuff or tweets in figurative or humorous or hyperbolic language. So is it possible that his use of "wiretap" is somehow metaphorical or purposely rhetorical?

If we take him at his word — that he really meant "surveillance" — I can think of two precedents in language use. Both have technical names. The first is metonymy (not to be confused with monotony); the second is synecdoche (not to be confused with Schenectady). Please stick with me.

Let’s begin with these definitions from the American Heritage Dictionary:

Metonymy: "A figure of speech in which one word or phrase is substituted for another with which it is closely associated, as in the use of Washington for the United States government or the sword for military power."

Synecdoche: "A figure of speech in which a part is used for the whole (as hand for sailor), the whole for a part (as the law for police officer), the specific for the general (as cutthroat for assassin), the general for the specific (as thief for pickpocket), or the material for the thing made from it (as steel for sword)."

From the evidence of those definitions — by not impugning the president’s motives — I could make a case that the president’s use of "wiretap" was both metonymic and synecdochic. Huh? This requires us to argue, in the first case, that "wiretap" is a word often used in association with "surveillance." In the other case, that "wiretap," a part, is being used to represent "surveillance," the whole.

But here, ladies and gentleman, I introduce to you one of my "biggest buts" of all time: I can find no evidence to suggest that the use of quotation marks will signal to any reader those subtle shifts in meaning.

This is not to say that quotations marks could not be used in this way. There is one well-worn usage of quotation marks to indicate that the speaker or writer means to indicate a different meaning of the word than its literal usage. Enter the "scare quote."

Here I am writing in "The Glamour of Grammar": "Then there is the use of quotation marks to create a mini-editorial, a veiled expression of opinion. I remember my anger as I read this commentary by Michelle Malkin in the immediate aftermath of 9/11:

'The media snobs are at it again. Wrinkling their noses at flag pins and patriotic ribbons. Tiptoeing around the word 'terrorism.' Preening about their precious 'objectivity,' 'neutrality' and 'independence.'"

Those last six quotation marks are not just punctuation. They are editorial language in disguise, a substitute for the phrase "so-called," an accusation that the claims of righteousness are false.

In The New Republic, Jonathan Chait argued that the editorial writers of The Wall Street Journal had mastered the technique of "scare quotes,” a phrase that can be traced back as far as 1960:

"The Journal also uses the device to imply skepticism about phenomena it finds ideologically inconvenient. Thus terms like 'the deficit' and 'inequality,' if they must appear at all on the Journal editorial page, are constantly set off in scare quotes."

Chait argues that such techniques: "also serve as a shortcut for the inattentive reader":

"Imagine a busy manager, quickly skimming over an editorial. He might come across a phrase like 'the deficit,' and suppose it’s a bad thing, or 'affordable health care,' and suppose it’s a good thing. The scare quotes would usefully signal the shortcut for the writers, allowing them to wallow in their ideological prejudices without spelling out their empirical premises. But maybe that Journal doesn’t really consider this a 'downside.'"

In his always helpful and measured Modern American Usage, Bryan Garner advises: "Reserve quotations marks for five situations. 1) when you’re quoting someone; 2) when you’re referring to a word as word…; 3) when you mean so-called-but-not-really…; 4) when you’re creating a new word for something …; 5) when you’re marking titles [of shorter works] …." Only number three suggests that what is inside the quotation marks signifies something other than its literal meaning."

The AP Stylebook says that quotation marks can be used to signify irony: "Put quotation marks around a word or words used in an ironical sense: 'The 'debate' turned into a free-for-all.'"

In an upcoming book, "The Quotable Guide to Punctuation," Stephen Spector offers this advice:

"When you put quotation marks around a word or a phrase to bring attention to it — especially if you do it in order to dissociate yourself from those words in some way — that’s called a 'scare quote.' They’re also known as 'shudder quotes' or 'sneer quotes.' They can suggest a skeptical or ironic tone, as if you’re saying "so-called" before the words or phrases….There’s an equivalent hand gesture in which you draw quotation marks in the air with two fingers when you say something. That’s called an air quote."

Spector warns, "One problem is that using quotation marks this way can be ambiguous. They could suggest skepticism, irony, or disdain, or they might simply mean that you’re using a word in an unusual way, or as slang."

So was President Trump being ironic when he put quotation marks around "wiretapping?" Clearly not. Was he showing disdain for the word or concept? No indication of that. By "wiretap," he did not mean, "the so-called wiretap."

We are left with a few other obvious interpretations: that this is Trump being Trump; that his administration — in the absence of direct evidence — has found a way to walk back his original accusation; that he and his reps are spinning his original language to achieve escape velocity from its literal meaning.

Or maybe we have something new here, an innovation in punctuation. “The Metonymic Quote,” a word or phrase that kinda, sorta, signifies what we mean.