particle N2 common casualpolitewritten
とは — what is called ~ (definition)
とは
Meaning
① definition: what is called ~ / the term ~ (means) — picks up a word to define or explain it, often in writing
② surprise: (to think) that ~! / the very idea that ~ — marks the preceding fact as shocking or unexpected
Key sentence
① definition
知的財産とは、発明やデザインなどの権利のことだ。
'Intellectual property' refers to rights over things like inventions and designs.
② surprise
まさか彼が犯人だったとは。
To think that he was the culprit…!
Formation
| Attaches to | Form | Example |
|---|---|---|
| Noun or plain-form clause + とは | [term / fact] + とは | 民主主義とは / 負けるとは |
Examples
① definition
自由とは、責任を伴うものである。
Freedom is something that comes with responsibility.
② surprise
こんな所で君に会うとは、驚いた。
To run into you in a place like this — what a surprise!
Easily confused with
Notes
- Definition とは is essentially と (quotative) + は (topic) — 'as for the thing called X'. The surprise sense usually ends the sentence on a falling, emotional とは…, leaving the reaction implied.
See とは in real sentences
Jengo shows とは the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Advanced Japanese Grammar.