What Is Gairaigo? A Guide to Loanwords in Japanese

Gairaigo (Japanese loanwords) are words borrowed from foreign languages and written in katakana. They make up roughly a tenth or more of the distinct words a learner meets.¹² The term covers borrowings from Portuguese, Dutch, English, and other modern languages. By convention, it excludes the ancient Chinese borrowings that form their own layer.³²

Overview

The word 外来語 (gairaigo) literally means "words that came from outside." The script often tells you the same thing at a glance: a word in katakana is usually a loanword.⁴⁵ This guide defines gairaigo against the other vocabulary layers, walks through the historical waves in order (Portuguese, then Dutch, then English), explains why katakana is the loanword script, and shows how much of the language gairaigo covers.

Everything here is pitched at the N5+ beginner. The example loanwords below (パン, コーヒー, ビール, テレビ) all appear on standard N5 word lists. The category labels 外来語 / 和語 / 漢語 themselves are advanced terms you do not need to read in Japanese yet.⁴

What Gairaigo Means

The literal sense of 外来語

The label 外来語 breaks down morpheme by morpheme: 外 (gai, "outside" or "foreign") + 来 (rai, "to come") + 語 (go, "word"), literally "word that came from outside."⁴² The scholarly definition closely follows that image.

A gairaigo is a Japanese word of foreign origin borrowed in modern times, chiefly from Portuguese, Dutch, English, and other modern languages.³² This definition deliberately excludes ancient borrowings from Old and Middle Chinese. Those form their own settled layer, called kango (Sino-Japanese vocabulary).⁴³

This makes the Japanese-studies sense of "loanword" narrower than the English word. By convention, gairaigo does not cover the kango layer, even though kango is also, historically, borrowed.⁴³

The label is kango, not gairaigo

The word 外来語 is itself written in kanji because it is a kango term; only the loanwords it describes take katakana. The name does not look like the thing it names.⁴

Gairaigo vs. the other vocabulary layers

Japanese vocabulary is conventionally split into four strata, known as 語種 (goshu, "word types").⁴¹ Gairaigo is one of these four.

Stratum	Reading	What it covers
和語	wago	Native Japanese words4
漢語	kango	Sino-Japanese words read with on'yomi4
外来語	gairaigo	Modern foreign loanwords4
混種語	konshugo	Hybrids combining two of the above4

The boundary between strata is porous. The word 歯ブラシ (ha-burashi, "toothbrush") is a konshugo hybrid: 歯 (ha) is native "tooth," and ブラシ (burashi) is the loanword "brush." A single word straddles two layers.⁴¹

This is where the "excludes ancient Chinese borrowings" convention matters. Kango entered from Chinese over a millennium ago and behaves like a settled native layer. It is counted separately from gairaigo, which marks recent foreign contact.³

A Short History of Borrowing

The chart below places the three borrowing waves in order. This shows the layers as centuries of accretion, not a single recent event. The two earliest waves, the Portuguese and Dutch pre-English loanwords, have their own dedicated guide.

The Portuguese layer (16th century)

The Portuguese were the first Europeans to reach Japan, arriving in 1543.⁶² Direct Japan–Europe trade and Jesuit missionary activity continued through the late 16th and early 17th centuries. They introduced new goods, foods, and Christian concepts, bringing the first wave of European loanwords.⁶

Several everyday words still in daily use trace to this contact.

Loanword	Portuguese source	Meaning
パン	pão	bread6
タバコ	tabaco	tobacco6
ボタン	botão	button6
カステラ	Castela	sponge cake6

These came with the new goods themselves: bread, tobacco, buttons, and confections.⁶² That is the classic way a loanword enters a language: a new object arrives with its foreign name.

パンを焼やきますか？⁷
"Do you bake bread?"

トム、パンをくれ。⁷
"Tom, give me the bread."

The Dutch layer (Edo-period sakoku, 17th–19th c.)

Under the sakoku (closed-country) policy, the Dutch trading post at Dejima in Nagasaki was the only Western channel into Japan from 1641 to 1854.⁸⁹ Loanwords entered through this single window during the Edo period.

Dutch knowledge transmitted through Dejima fed a field of study called 蘭学 (rangaku, "Dutch learning").⁹ The 蘭 (ran) is clipped from オランダ (Oranda, "Holland"), and 学 (gaku) means "study." This is why Edo-era Western science vocabulary has a Dutch flavor.⁹

Loanword	Dutch source	Meaning
ガラス	glas	pane glass8
ビール	bier	beer8
コーヒー	koffie	coffee8
ガス	gas	gas8

One pair shows the borrowing route. ガラス (pane glass, from Dutch) and the later English-route グラス (a drinking glass) are two separate borrowings of the same European word at different times.⁸

コーヒーはどう？⁷
"How about some coffee?"

ビールを一杯いっぱいどう？⁷
"How about a beer?"

The English wave (Meiji to the present)

The Meiji Restoration of 1868 restored imperial rule and opened Japan to rapid Westernization.¹⁰² From this point, contact with European languages, especially English, became the dominant source of new loanwords.

During the Meiji era (1868–1912), the donor languages were still mixed, with German for medicine and French for some military and arts terms.¹¹² English was already rising, and through 20th-century globalization it became overwhelmingly dominant.

About 80% to 90% of gairaigo are of English origin.¹¹² The English share has climbed over time. One source notes that in 1911–1924, about 51% of dictionary-listed gairaigo were English, compared with the much larger majority since.¹¹²

Borrowing is an ongoing process

Gairaigo is not a finished historical deposit. New loanwords keep entering, most of them from English, as new concepts and products arrive named from abroad.¹¹²

テレビって見みる？⁷
"Do you watch TV?"

テレビを消けして！⁷
"Turn off the TV!"

Why Loanwords Are Written in Katakana

Katakana as the script of the foreign

Modern written Japanese divides work across three scripts. Kanji and hiragana carry native (wago) and Sino-Japanese (kango) words and grammar. Katakana is most often used to transcribe gairaigo.⁵

The Japanese government codified katakana as the standard loanword script. The Agency for Cultural Affairs' Cabinet Notification "外来語の表記" (No. 2, 28 June 1991) sets out the kana and symbols to use. These are for writing loanwords, foreign place names, and foreign personal names in general writing.¹²¹³

Because katakana is reserved this way, the script is a visual flag. Seeing a word in katakana is a reader's first cue that the word is probably gairaigo, a foreign name, or otherwise marked. It stands apart from the surrounding kanji-and-hiragana text.⁵

Let the script do the first sort

When you meet an unfamiliar word in katakana, your first guess should be "foreign loanword." Then check. The script narrows the field before you reach for a dictionary.⁵

When the rule bends

A few well-worn early loanwords historically took kanji spellings (ateji) even though they are gairaigo and keep their foreign pronunciation.² The word 煙草 is read tabako ("smoke-grass," tobacco), and 珈琲 is read kōhī (coffee). These survive in signage and stylized writing.²

Katakana also does jobs other than marking loanwords. It carries onomatopoeia such as ピンポン ("ding-dong"), scientific names of plant and animal species, and emphasis used the way English uses italics.⁵

So "katakana = loanword" is a strong default, not an absolute. Most loanwords are katakana, but not every katakana word is a loanword, and a handful of loanwords wear kanji.²⁵

How Much of Japanese Is Gairaigo

Roughly a tenth of the words you meet

Common reference estimates put gairaigo at roughly 10–15% of modern Japanese vocabulary.¹² The figure varies by corpus, date, and counting method: distinct word types or running tokens.

The Balanced Corpus of Contemporary Written Japanese (BCCWJ, NINJAL, 2011) gives a more precise split.¹ Gairaigo make up about 5% of running text by token but roughly 19% of distinct word types. In other words, loanwords are individually less frequent but contribute a large share of the vocabulary's variety.

The native (wago) and Sino-Japanese (kango) strata together still account for the bulk of actual running text.¹ The loanword share has also risen across the 20th century. It moved from low single digits by token early on to several times that by the 2000s, so any single percentage is a snapshot, not a constant.¹

Quote the share with its caveat

There is no single honest percentage for "how much is gairaigo." State it as a range, and say whether you mean word types or running tokens. The BCCWJ figures (≈5% by token, ≈19% by type) show how far the two diverge.¹

English dominates the stratum, at about 80% to 90% of gairaigo, so most of that slice is English-derived.¹¹²

Where the density spikes

Loanword density is uneven across registers. It spikes in technology and IT, business, fashion, food and dining, and sports. In these areas, new concepts and products often arrive with foreign names faster than native coinages appear.¹²

This is where katakana literacy pays off fastest for a learner. A tech article, business document, or menu can be dense with katakana loanwords even when its surrounding grammar is elementary.¹

Good to know

Not every katakana word is a loanword

It is tempting to treat "written in katakana" as a reliable test for "foreign loanword." But the script has several jobs, and loanword-marking is only the most common one.⁵ The word キラキラ ("sparkle, glitter") is native Japanese onomatopoeia written in katakana for effect, not a borrowing at all.⁵

Katakana also carries scientific species names and emphasis, so the script is a strong hint, not proof.⁵ Read it as "probably foreign, now confirm," not as "definitely foreign."

Pronunciation drifts from the source

A loanword's sound is reshaped to Japanese phonology and mora timing, so it is not the source-language sound.¹¹⁵ English "strike" is one syllable. In Japanese, it becomes ストライク (sutoraiku), five morae, with vowels inserted to break up the consonant clusters.¹¹⁵

This matters when you try to say the word. You cannot pronounce a katakana word by reading its English spelling. You read the katakana, which encodes the Japanese shape of the borrowing.¹¹

"Looks English" is not "is English"

Some katakana words look English but do not mean what the English word means. This is the wasei-eigo ("made-in-Japan English") trap: Japanese-coined pseudo-English words and re-meanings that are not standard English.²

The visual "Englishness" does not tell genuine loans apart from home-grown coinages assembled from English parts.² The trap is real and worth knowing about here, though it is a sibling topic covered elsewhere.

See also

• Shortened Loanwords in Japanese: Why パソコン, リモコン, and アポ Get Clipped
• How to Write Your Name in Katakana: Foreign-Name Transcription Rules with Examples
• The History of Katakana: From Heian Monks' Shorthand to the Modern 46-Character Set
• Hiragana vs. Katakana: How to Tell Them Apart and Use Both
• The Complete Katakana Chart (Gojūon): How to Read All 46 Base Kana, Dakuten, and Yōon

References

Footnotes

1. 国立国語研究所 (NINJAL). 『現代日本語書き言葉均衡コーパス』 (Balanced Corpus of Contemporary Written Japanese, BCCWJ), 2011; lexical-stratum (語種) statistics. https://clrd.ninjal.ac.jp/bccwj/en/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

2. Wikipedia. "Loanwords in Japanese" (definition; "80% to 90% of gairaigo are of English origin"; historically kanji-spelled loans 煙草, 珈琲). https://en.wikipedia.org/wiki/Loanwords_in_Japanese ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹

3. Frellesvig, Bjarke. A History of the Japanese Language. Cambridge University Press, 2010 (history of borrowing; Old/Middle Chinese vs. modern foreign borrowing). https://www.cambridge.org/core/books/history-of-the-japanese-language/ ↩ ↩² ↩³ ↩⁴ ↩⁵

4. Shibatani, Masayoshi. The Languages of Japan. Cambridge University Press, 1990, ch. 6 (vocabulary strata: wago / kango / gairaigo). https://www.cambridge.org/core/books/languages-of-japan/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²

5. Wikipedia. "Katakana" (katakana as the standard script for gairaigo, foreign names, onomatopoeia, scientific names, and emphasis). https://en.wikipedia.org/wiki/Katakana ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

6. Wikipedia / academic compilation. "Glossary of Japanese words of Portuguese origin." (Portuguese source words; 1543 first contact.) Cross-checked against Wiktionary entries for tabaco, botão, pão. https://en.wikipedia.org/wiki/Glossary_of_Japanese_words_of_Portuguese_origin ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

7. Tatoeba Project. Sentence corpus, CC BY 2.0 FR. Individual sentence IDs cited inline. https://tatoeba.org ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

8. Wikipedia / academic compilation. "List of Japanese words of Dutch origin" (Dejima 1641–1854; Dutch source words glas, bier, koffie). https://en.wikipedia.org/wiki/Glossary_of_Japanese_words_of_Dutch_origin ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

9. Britannica. "Rangaku." (蘭学 = Dutch learning; ran < Oranda; sakoku channel for Western knowledge.) https://www.britannica.com/topic/rangaku ↩ ↩² ↩³

10. "Meiji Restoration." Encyclopaedia Britannica / Wikipedia (1868 imperial restoration and rapid Westernization). https://en.wikipedia.org/wiki/Meiji_Restoration ↩

11. Daulton, Frank E. Japan's Built-in Lexicon of English-based Loanwords. Multilingual Matters, 2008 (English now dominant donor; ~80–90% of modern gairaigo). Cross-referenced with the figure cited in Wikipedia, "Loanwords in Japanese." ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

12. 文化庁 (Agency for Cultural Affairs). 「外来語の表記」, 内閣告示第二号 (Cabinet Notification No. 2), 28 June 1991 (平成3年). https://www.bunka.go.jp/kokugo_nihongo/sisaku/joho/joho/kijun/naikaku/gairai/index.html ↩

13. 国立国語研究所 (National Diet Library record). 「外来語の表記 : 内閣告示・内閣訓令」, 1991. https://ndlsearch.ndl.go.jp/en/books/R100000001-I27210000386908 ↩