I was tallking off the top of my head, as I was in a meeting and didn’t have a dictionary. In the context I used the word, I was probably inferring it’s connotation (manipulation) not its definition.
Your boss is the Pointy Hair Boss
A gazillion eons ago when I was still on active duty, deployed to Sicily, and frequently bored, I used to flip open the dictionary looking for new and exciting words. The maintenance control chiefs thought this was hilarious, and frequently asked me for the word du jour. Off the top of my head, I recall sharing *persiflage * and panache - I was already familiar with panache, but it was still worth sharing.
They didn’t mock me - at least, not to my face. After all, I was a mighty Lt j.g. at the time. <cue fanfare>
This is TOO good!
And I LOVE the image of you having to report to his office with a dictionary. What is this, pre-school?
Huh?
Your first use of the word “boundary” is not the same as your second use. The first boundary no longer exists, so it makes no sense to say that the number of people in it has changed.
Yes, the *purpose *of gerrymandering is to create a political district with a particular population distribution, but that doesn’t mean that the *definition *of gerrymandering is the manipulation of numbers. In a limited sense, gerrymandering might be considered to be one example of number manipulation, but that is all.
I suggest you tell him to play this game.
I agree with Contrapuntal, the OP used the term gerrymander incorrectly. It has no other definition than the redrawing of political district boundaries for partisan reasons. It would be incorrect to say that General Petraeus gerrymandered Iraq casualty figures to give the troop surge a greater appearance of success.
But it doesn’t make the OP’s boss any less of an idiot.
I disagree. If you consider that departments are analogous to political districts, and those not working over the holidays are analogous to, say, Republicans, then it makes perfect sense. Instead of physically redrawing the district lines, you’re changing what department people are working for during the holiday season. In other words, each department now has the required amount of Democrats.
I think the word was used correctly.
Nobody in the meeting had a laptop to look up a word?
No, use curmudgeon. And if he asks for the dictionary, tape a mirror to the opposite page. 
If blood is analogous to pizza, then a transfusion can correctly be called a take-out order.
If you are not talking about redrawing political lines, you are not talking about gerrymandering. And yes, the boss is a doofus. I did not mean to suggest otherwise.
Nice try, but, if blood was analogous to pizza, a transfusion would be a “put-in” order. 
The point is, you’re rearranging what departments (districts) people are in, in order to fill a need, which is enough workers (voters) available. Instead of redrawing political lines, you’re redrawing departmental lines. I think it’s a great analogy. Obviously, YMMV.
Hey! You don’t get to take it with you? You’re getting ripped off!
It may or may not be. Analogies are not definitions, however. If he had said “It’s like gerrymandering,” perhaps. He didn’t. He said that it *was *gerrymandering.
This reminds me of the time, in a staff meeting with Brunhilde the Barely Knowledgeable Boss, I said “that’s a fallacious statement!”. Guess what she thought ‘fallacious’ meant?
Perhaps you should simply boycott meetings. But I love the suggestion that you demand … oops … request … a list of all the other words pointy-haired boss doesn’t know. 
I bet Scott Adams would like that story: perhaps you should wrap the story up in pretty shiny paper and send it to him as a Christmas present.
(I once had everyone in the office (ahem library) flummoxed when I used the word “pedantic”. It was strange trying to explain without sounding too, well, you know).
Let’s compromise. He should have said, “I had to, like, gerrymander it, duh. Gosh.” 
Hey, I had no problem with his usage until he offered a definition that was incorrect. Ain’t no thang.
So he used a metaphor instead of a simile.
From here:
I also checked several dictionaries, and they only have the political district manipulating meaning.
From here:
There are many words in play that describe the process of manipulating resources. There are many words that describe the process of manipulating numbers.
Gerrymandering is not one of them, although Gerry Mander did play the Beaver in Leave it to Beaver. No, that was Jerry Mathers, who died in Vietnam - you can look it up on the interweb.
One of the standard Bullshit Boss Sayings is that good bosses want everyone else in the room to be smarter than they are. I don’t believe it for a minute. There’s a special brand of boss who needs to either actually be the smartest person in the room, or to have the illusion of such. These bosses generally don’t like it when an employee shows any sign of being smarter or better educated - especially in a meeting.
I call “asinine hijinks” on that.