とはX means…; to think that…
After a word, とは says what it means: the written というのは. After a whole statement, it is surprise at a fact: "I never thought…", "to think that…".
defining a word
Coexistence means different kinds of people living together while respecting one another.
surprise at a fact
I never thought we would get here this early.
Defining a word
Word + とは、+ what it is + （の）ことだ／ものだ／である
The word is often in 「 」. The explanation ends in a noun, or in を指す, "refers to".
Surprise at a fact
Plain form + とは（+ 思わなかった／驚いた／信じられない）
A noun or a な-adjective takes だ, which is often dropped: 彼が犯人（だ）とは. The sentence can stop at とは.
Defining a word
Dictionaries, textbooks, contracts and reports say what a term means this way. In conversation, the same sentence starts with というのは or って.
The "shihatsu" is the first train or bus of the day.
In a dictionary or a textbook.
The "shihatsu" is the first train or bus of the day.
In a lesson, or explaining at work.
The "shihatsu" is the first train or bus of the day.
To a friend.
In this report, "the region" refers to the five districts within the city.
Trust is something built over time.
Not only for terms. Sayings and speeches use it to say what a thing really is.
What is freedom? Answering this question is not easy.
とは何か, "what is…?", opens essays and lectures. As a heading it is often cut to 〜とは？.
Surprise at a fact
Something has turned out to be so, and you can hardly take it in. It can be dismay or admiration. What you felt comes next. とは思わなかった, "I never thought…", is said every day. Before a reaction such as 驚いた or 信じられない, とは is written style, and conversation mostly uses なんて.
I simply cannot believe that he would break his promise.
Running three companies at that age: that is quite something.
I was amazed that this quiet young man could be so bold on stage.
Stopping at とは
The feeling is often left unsaid, so that the sentence hangs at とは, often with まさか at the front. It sounds dramatic: you meet it in novels and dramas, and when someone mutters to themselves. とはね is lighter.
To think he climbed all the way to the summit alone!
I never thought I would run into you here.
Sold out in a week. Who would have thought?
Close neighbours
というのはN3
The spoken version, for lessons and everyday talk.
An "asaichi" is a market held in the morning.
とは限らないN3
No surprise here. Before 限らない or 言えない, the statement is a rule or a guess that you don't fully accept, not a fact that has turned out true: "not always", "you can't say that…".
Expensive products don't always last long.
Check yourself
1Which sentence says what a word means?
Choose an answer to see why.
2What does this mean?
まさか、
Choose an answer to see why.
More detail
The word being explained can be a verb: 学ぶとは何か, "what it means to learn".
I would like to think again about what it means to learn.
More sentences
Renewable energy is energy obtained by using natural forces.
"Zantei" is a word for a temporary measure that holds until a final decision is made.
Independence here does not mean never accepting anyone's help.
I was truly amazed that an unknown athlete broke the world record.
I never dreamed that a manuscript thought lost would turn up after a hundred years.