Translation guide
The English phrase "that is" has two main functions: clarifying or rephrasing something just said, and as a fixed phrase meaning "in other words" or "namely." This guide covers natural Japanese equivalents for each use.
To explain or restate something more clearly, often used in speech or writing.
The most common and versatile equivalent. Used to rephrase or summarize what was just said. Suitable for both spoken and written Japanese.
To introduce a specific list, explanation, or definition.
つまり is the everyday word for 'that is' or 'in other words.' すなわち is more formal and often used in written definitions or lists. In casual conversation, つまり is preferred.
つまり、何が言いたいの？
So, what are you trying to say?
すなわち、この問題は解決された。
That is, this problem has been solved.
Avoid directly translating 'that is' as それは...です (sore wa... desu) when you mean 'in other words.' That would mean 'that thing is...' and is incorrect for this function.
彼は、つまり私の兄は、医者です。
He, that is my older brother, is a doctor.
明日までに、つまり金曜日までに、レポートを提出してください。
Please submit the report by tomorrow, that is, by Friday.
More formal and often used in writing or speeches. It means 'namely' or 'that is to say.'
日本の首都、すなわち東京は、大都市です。
The capital of Japan, that is, Tokyo, is a large city.
Literally 'if we say it differently,' used to rephrase something in other words. Common in both speech and writing.
彼は、言い換えれば、あまり正直ではない。
He, that is, is not very honest.
The standard formal equivalent for 'namely' or 'that is to say.' Often used in definitions or to introduce a list.
三原色、すなわち赤、青、黄色。
The three primary colors, that is, red, blue, and yellow.
Can also be used for 'namely,' but slightly less formal than すなわち. Common in everyday explanations.
彼は三つの言語、つまり英語、日本語、中国語を話します。
He speaks three languages, that is, English, Japanese, and Chinese.