GrammarJLPT N5
→ topic definition marker
Indicates a Word or Phrase Being Defined
JLPT N5Compound particleNeutral
The compound particle とは is used to mark a word, phrase, or concept that the speaker is about to define, explain, or express surprise about. In its definitional use, とは functions similarly to saying 'X means...' or 'What we call X is...' in English, and it is commonly found in dictionary entries, textbooks, and explanatory writing. It combines the quotation particle と with the topic particle は, essentially quoting the term and then setting it up as the topic for definition. Beyond definitions, とは also appears in exclamatory sentences where the speaker expresses surprise or disbelief that something has happened, carrying a nuance of 'I can't believe that...' or 'To think that...'. This usage conveys strong emotion and is somewhat literary or dramatic in tone. The more casual equivalent of definitional とは is って, while the longer form というのは is a softer, more conversational alternative. Learners should note that とは in its definitional role sounds relatively formal or written, whereas its surprise usage can appear in both spoken and written Japanese.
Functions
#1 Defining or explaining a term
Structure
Noun / Phrase + とは + explanation + だ / のことだ
「花見」とは、花を見ながら楽しむことです。
Here とは marks the word 花見 as the term being defined. The particle と quotes the word, and は sets it as the topic, after which the explanation follows. This pattern is extremely common in dictionaries, encyclopedias, and classroom explanations. The sentence ends with ことです, a typical way to wrap up a definition. This is the most fundamental use of とは."Hanami" means enjoying oneself while looking at flowers.
Structures
- Defining a term
- Noun / Phrase + とは + definition / explanation + だ / です / のことだ
- Expressing surprise
- Clause (plain form) + とは + surprise expression (or standalone)
Common mistakes
A common mistake is confusing とは with というのは in terms of register; とは is more concise and formal, while というのは sounds softer and more conversational, so using とは in casual speech for definitions can sound stiff. Another frequent error is using とは for surprise when the sentence does not describe something genuinely unexpected, since this usage inherently carries strong emotion and sounds unnatural with mundane facts. Learners also sometimes forget that the clause before とは should be in plain form, not polite form, writing です or ます before とは when it should be だ or the dictionary/た form of a verb. Finally, some learners confuse とは with とは限らない (not necessarily), which is a separate fixed expression and should not be broken apart as simply とは plus 限らない.
Related
というのはってとは限らないとは言えとは思わなかったというのは～ということだ