というのは

Meanings

because; the reason is

usually written using kana alone

Used to explain a reason or cause, often at the beginning of a sentence or clause. Equivalent to 'the reason is that...' or 'because...'.

彼かれは遅ち刻こくした。というのは、電でん車しゃが遅おくれたからだ。
He was late. The reason is that the train was delayed.
今日きょうは休やすみます。というのは、熱ねつがあるんです。
I'll take the day off. That's because I have a fever.

expression, conjunction

as for; regarding; when it comes to

usually written using kana alone

Introduces a topic or subject, similar to 'speaking of...' or 'as for...'. Often used to clarify or ask about something previously mentioned.

というのは、昨日きのうの話はなしのことですか。
Are you talking about what we discussed yesterday?
彼かの女じょはとても親しん切せつだ。というのは、いつも手伝てつだってくれるからだ。
She is very kind. I mean, she always helps me out.

Grammar

というのはX means…; the reason is…N3

Kanji

言say, word

Related words

なぜならN3sense 1
なぜなら is a more formal, often written way to introduce a reason, while というのは is more conversational and can also introduce a topic.
とは
とは is a contracted, everyday form used to introduce a definition, while というのは is more explicit and formal, often used in careful explanations.
なぜならば
というのは introduces a clarifying reason or explanation in a slightly softer, more discursive way than the formal なぜならば.

Don't confuse with

つまりN3sense 2
つまり is used to summarize or rephrase what was just said, whereas というのは introduces a reason or clarifies a topic, so learners often swap them incorrectly.
というもの
というもの refers to a thing or concept by name within a sentence, while というのは introduces a definition or explanation of a term, often translated as 'the reason is' or 'that is to say'.

Etymology

Combination of quotative と, verb 言う (to say), and explanatory の + topic marker は. Literally 'as for saying that...', it developed into a conjunction for giving reasons or introducing topics.