A lot of Japanese words have popped up in English over the years. We could pick out a bundle brought back by soldiers after the war ("A skosh more whiskey, barkeep!"), another handful arriving during later trade troubles ("We're bringing in a kaizen specialist to re-prioritize our manufacturing paradigms!"), and a recent crop imported by pop culture fans ("I just love anime, don't you?"), with surely more to arrive via new routes. Words don't often jump languages with meaning intact, though, and many Japanese loanwords are no exception. Let's look at a few words that have found a new life – and some new meanings – in English.

First, an important point: In all of my examples, the new meanings don't differ radically from the old. In other words, none of the new "foreign" meanings are outrageously wrong. In fact, those meanings don't need to be seen as "wrong" at all, but rather as perfectly valid definitions for new English words! For clarity, I'll write those new English words normally, and use italics when referring to the original Japanese word.

Also, understand that the "you" in this article is suppositional. You personally are probably square with the original meaning of many (maybe all!) of the below. So take the "you" in stride; my point is simply that for each of the below, there are some English speakers who mistake the meaning they know for the original meaning in Japanese.

So, just for the fun of pointing out changes that accompany the overseas migration of words, here we go. In alphabetical order: 

anime

What you think it means

Animated media from Japan, or in a recognized "Japanese" style

What it means in Japanese

Animated media - i.e., cartoons - from any place, in any style.

Commentary

The Japanese word anime アニメ is an abbreviation of "animation" アニメーション – and means nothing more and nothing less than that. Anime is animation, any animation. Cinderella, Tetsuwan Atom, Sailor Moon, The Simpsons, dancing vowels on Sesame Street; it's all anime.

If you're communicating in Japanese and want to specify Japanese animation, you'll have to do just that. Try Nihon no anime or some such wording. (Incidentally, should I ever find myself at an American "anime convention" talking to fans in English, I'll unapologetically refer to the objects of their adoration with the perfectly applicable English terms "cartoons" or "Japanese cartoons". Somehow I don't think that'll be welcomed, though I really couldn't say why. Any fans have a take on that?) 

Yes, this is anime

banzai

What you think it means

A military cheer calling for or celebrating victory in war.

What it means in Japanese

An all-purpose cheer, with or without any military overtones. 

Commentary

Yay! Hurrah! Huzzah! Long Live the Queen (or whoever)! Hip Hip Hooray! (Does anyone say that any more?) GOOAAALLL!

The shout banzai – typically with both arms swung upward in time with the cries – is the same cry as the above: a generic cheer of enthusiasm, victory, or support. It's a Chinese-derived term meaning "ten thousand years", used in Chinese (萬歲 or 万岁, wànsuì) and Korean (만세, manse) as well. The implication, of course, is a wish that the lauded accomplishment or person should continue on for ten thousand years. It's essentially the same as "Long live [the Queen / the Republic / disco / whatever]!", but ten thousand years long.

It should come as no surprise that the cheer found ample use in war, and that's where the English-speaking world became familiar with banzai as a battle cry of Japanese soldiers wishing the Emperor and the Japanese Empire an effective eternity of existence. Banzai will no doubt continue to be heard in every future Pacific War pic made, and there's nothing inaccurate in its depiction as a soldier's cheer.

But here in the present, should you hear shouts of banzai coming from a Japanese sports team, an electoral victory party, or just a bunch of Shinjuku drunks, don't fear. The worst that might follow is celebratory sake, not a squad of Zero fighters.

 A classic banzai moment in politics. No soldiers in sight. 

kaizen

What you think it means

Continuous improvement, or a Japanese business philosophy of continuous improvement.

What it means in Japanese

Improvement. No "continuous", no "Japanese business philosophy", just generic "improvement".

Commentary

I've got a whole article covering kaizen, so head there for the full story. The short version is this: The Chinese-derived word kaizen 改善 (still in use in Chinese, and Korean as well) has no intrinsic meaning in Japanese of "continuous improvement" or "business philosophy" or any such deep stuff. It has the same generic, mundane meaning as the English word "improvement", and can mean any improvement big or small, one-time or ongoing, with or without a hint of attached "philosophy".

Meanwhile, the modern word Kaizen as "a Japanese business philosophy of continuous improvement" is an invention by speakers of other languages. Nothing wrong with that, though one wonders what's actually Japanese about it... but, that's a matter for the article.

 A sterling example of kaizen in action.

katana

What you think it means

A Japanese sword with specific well-known design elements, including a two-handed hilt and a single-edged curved blade.

What it means in Japanese

Any single-edged, curved sword, whether Japanese samurai's sword, French cavalry saber, Persian scimitar, or whatever fits that broad description.

Commentary

The Japanese katana is perhaps most identical to the English "backsword", a name for single-edged swords that's no doubt more obscure to the average English speaker than is "katana". As is often the case with words hoplological, the range of weapons covered by katana isn't crystal clear, but any single-edged sword is likely to fit in there. While katana is written with the single Chinese character 刀, it originally derives from kata (one side) and na (an archaic term for blade). (Incidentally, a more generic Japanese term for sword, whether single- or double-edged, is tsurugi 剣; that word is easily translated into English as the generic "sword".)

So, one sees katana in Japanese applied to any single-edged sword, from anywhere in the world. That includes single-edged Japanese swords as well, of course. But if you want to specify a Japanese single-edged sword in Japanese, you'll do better with nihontou (from nihon 日本, Japan; and tou 刀, a Chinese-derived alternate reading of the character for katana). Something like Nihon no katana or samurai no katana would work too. 

Fun note for the geeks: Wikipedia's English Katana page is linked to the Japanese nihontou page, informing Japanese readers that nihontou is what the English speakers actually mean when they say katana. Meanwhile, the Japanese katana page is linked to the English Backsword page, reflecting the actual equivalence of the Japanese word katana with the English word "backsword". (It's also interesting to note that, as of this writing, the Japanese katana page uses an image of a French naval officer saber to illustrate katana. That's a beautiful example of how katana in Japanese does not mean "samurai sword"!)

 US Marine with actual Marine katana

manga

What you think it means

Illustrated comics or comic books from Japan, or in a recognized "Japanese" style

What it means in Japanese

Comics. Comic strips. Comic books. The funny pages. From any place, in any style.

Commentary

The Japanese word manga 漫画 uses two Chinese characters essentially meaning "comic picture(s)". And, like anime, the Japanese word's meaning is generic and all-inclusive, with no intrinsic hint of national origin. Peanuts, Black Jack, Superman, a political cartoon, witty old ukiyoe drawings, that bad caricature of your face you got drawn at the carnival; it's all manga. (Accordingly, Wikipedia's Japanese manga page uses an old-timey American strip to illustrate the concept of manga.)  

If you're communicating in Japanese and want to specify Japanese comics, you'll have to do just that. Try Nihon no manga or some such wording. 

And as I mentioned with regard to anime, should I have a need to discuss Japanese comics in English, I'll refer to them as "Japanese comics" or just "comics", not "manga"; why wouldn't I do so? Oh, then we've got the people who will actually say, while speaking English, "Japanese manga" or "Japanese anime". Huh? I don't even know what to make of that.

(What's with the rampant fascination with country of origin when discussing cartoons and comics, anyway? I don't get it.) 

 Enough learning; time for some genuine manga!

Well?

Was any of that of interest? If so, say so; there are plenty more words where those came from! 

Maybe you've got some suggestions of your own, too?