X 也就是 Y
Reach for 也就是 when you've said something dense, jargony, or roundabout, and now you want to rephrase it in plainer words — 'X, that is to say, Y.' Common in explanatory writing, podcasts, lectures, and any moment when you suspect your listener didn't fully get the first version. Slightly formal; the spoken cousin is '就是' or '换句话说'.
Structure
[X], 也就是 [Y] / [X], 也就是说 [Y]
...yě jiùshì... / yě jiùshì shuō...
How to Think About It
也就是 is an equals sign in the middle of a sentence. X and Y point at the SAME thing — Y is just X said more usefully (a definition, a number translated into plain language, a fancy term turned into ordinary words). Adding 说 — 也就是说 — pulls the focus onto the rephrasing act itself ('what I mean is...'). Without 说, the pattern just glues two labels together; with 说, you're stepping in to clarify.
Examples
他是程序员, 也就是写代码的人。
Tā shì chéngxùyuán, yě jiùshì xiě dàimǎ de rén.
He's a programmer — that is, someone who writes code.
他下周来, 也就是说我们还有时间准备。
Tā xià zhōu lái, yě jiùshì shuō wǒmen hái yǒu shíjiān zhǔnbèi.
He'll arrive next week — meaning we still have time to prepare.
她退休了, 也就是不用再上班了。
Tā tuìxiū le, yě jiùshì bù yòng zài shàngbān le.
She's retired — in other words, she doesn't have to work anymore.
Common Mistake
Learners use 也就是 for any 'and also' or 'in addition' relationship, treating 也 as a coordinator. Here, 也就是 is a fixed phrase meaning 'that is.' Don't put new information in Y — Y has to be a restatement, not an extension.
他是医生, 也就是他妻子是老师。
他是儿科医生, 也就是专门看小孩的医生。
Don't Confuse With
就是
More casual restatement, common in speech. 也就是 sounds more measured and explanatory. In writing, prefer 也就是; in chat, 就是 is fine.
换句话说
'In other words.' Stronger pivot — you're explicitly resetting the explanation. 也就是 is a softer aside; 换句话说 is a deliberate paraphrase.
比如
Introduces an EXAMPLE of X, not a restatement of X. '水果，比如苹果' (fruit, for example apples) vs. '水果, 也就是含水分的食物' (fruit, that is, water-containing food).
Practice
他来了, ___ 我们可以开始了。
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也就是说
AI, ___ 人工智能, 最近发展得很快。
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也就是
Put in order: [她 / 也就是 / 老板 / 是 / 我的 / CEO]
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她是CEO, 也就是我的老板。
Translate to Chinese: 'He didn't come, which means we have to wait.'
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他没来, 也就是说我们得等一下。
Write one sentence that defines a word or restates an idea, using 也就是.
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Example answer: 北漂，也就是在北京打工的外地人。 (Beipiao — that is, out-of-town workers living in Beijing.)