In English, we would probably say that fortune, fortunate and unfortunate belong to the word family fortune. A Japanese analogy would most likely place 返{かえ}る and 返{かえ}す in the same language family. Learning language families is an effective way to learn patterns and not actively study too many similar words. Not being a native however, there are words that are not as clear-cut as the example above, and it would be nice to know if there is a list somewhere of word families. Universities, education ministries and the like tend to produce such material.

It would also be interesting to know if there is any such system for Chinese loan words. Would 手本{てほん} be considered a word family? Or would rather the morphemes, that is, 手{て} (hand) and 本{ほん} (book) be regarded as the word families?

Note that I am not saying a kanji is a morpheme or a word family. 明日{あした} and 明日{みょうにち} would in my mind be different word families.

What I'm after, preferably, is some kind of established norm of how to sort words as effectively as possible, such as the concept of language families, since that would be a good reference as a second language learner.

2 Answers 2


It sounds like you're talking in part about approaches to organize your own efforts in studying and understanding the language.

As naruto notes, there are a couple different terms that you could use to talk about or search for these kinds of terms:

  • 同根語【どうこんご】 (Weblio bilingual entry), literally "same + root + word/language", meaning "cognate term".
  • 同系語【どうけいご】 (Kotobank, in Japanese), literally "same + thread + word/language", meaning "cognate language" → also used colloquially to mean "cognate term", while in academic resources, this appears to refer to related languages coming from the same proto roots, such as Spanish and French both arising out of Latin.
  • Possibly also, 語源的【ごげんてき】に関係【かんけい】ある言葉【ことば】, literally "etymologically + related + words". This is a long phrase, more something you'd use when talking to people than something you could usefully google for.

That said, when it comes to your own research and "how to sort words as effectively as possible", I'd advise looking for roots. Japanese verbs have historically been very productive, with various aspect and other suffixes giving rise to a rich and nuanced vocabulary. When looking at verbs, the core stem or root is usually the first two morae: start there, and see if that opens any further doors.

Over time, you'll come to recognize more and more of the various suffixes (often called "auxiliaries" or 助動詞【じょどうし】 – see also the Japanese Wikipedia page), things like ~う (from older ~ふ), indicating repeated or ongoing action or state (and derivatives ~わる・~える); ~む and ~ぶ, indicating that something "looks like / seems like / behaves like / becomes like" something else (and derivatives ~まる・~める・~びる); or ~す, indicating a transitive or causative sense (and derivatives ~せる・~させる).

From there, you're off to the races, as it were -- you'll be equipped to see how words break down, like あらわれる arising from copula ("to be" verb) あり + iterative / repetitive ふ + passive / spontaneous れる: "to be coming into being on its own → to appear, to become manifest". Or あつめる arising from adjective stem あつ ("thick, dense") + "becomes like" む + shifted to transitive ending ~える.

Happy digging!


I think 類語 (literally "group word") is what you are looking for. 類語 is often used loosely, and it often has a broader sense than 同義語 ("synonym"). For example, I hesitate to say 返す and 返る are 同義語 because they are almost never interchangeable, but I believe it's safe to say they are 類語. Even antonyms like 男/女 may be called 類語, too.

I don't think there is an authoritative list of 類語 maintained by the government or a university, but there are a number of commercially-available Japanese thesauri. Taishukan's 日本語シソーラス 類語検索辞典 第2版 is one of the most recent.

As far as meaning is concerned, 手, 本 and 手本 are unrelated words. If you are looking for lists of words sharing the same kanji, try some 漢和辞典. On the other hand, あす, みょうにち and あした are undoubtedly 類語 (as well as 同義語) because they all mean "tomorrow".

EDIT: If you're looking for a word that specifically refers to "words that share the same etymology (but don't necessary share the same meaning today)", 同根語 (cognates; literally "same root word") is the term for that concept. But note that, while this is an interesting topic for linguists, it's not necessarily so for ordinary language learners.

  • 2
    I think one of the important elements of "word families" as a concept in English is that all the members of a "family" share the same etymological link. This Wikipedia article gives the example of "wrought" and "work", which are in the same family, despite the fact that even native speakers would be unlikely to guess they are linked in etymology. There doesn't seem to be a corresponding Japanese language article for the subject. 類語 is a concept I think the OP will find interesting, but it doesn't have the same etymology requirement.
    – Leebo
    Jul 3, 2022 at 23:42
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    @Leebo Ah, you're right, I didn't know the meaning of "word family". Then something like 同系語 might work (although this is used both for languages and individual words).
    – naruto
    Jul 4, 2022 at 2:14

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