ということは

と

い

う

こ

と

は

Common word

Meanings

expression, adverb

that is to say; so that means; in other words

usually written using kana alone

Used to rephrase or draw a conclusion from what was just said; often appears at the beginning of a sentence.

彼かれは今日きょうも遅ち刻こくした。ということは、また寝ね坊ぼうしたんだろう。
He was late again today. So that means he probably overslept again.
A：明日あしたは祝しゅく日じつだよ。B：ということは、学がっ校こうは休やすみか。
A: Tomorrow is a national holiday. B: That means school is off, right?

Grammar

ということはso that means…; which means…N2

Kanji

言say, word
事matter, thing, fact

Related words

つまりN3
つまり is a more direct way to say 'in short' or 'that is to say', while と言うことは specifically draws a logical conclusion from what was just said.
すなわちN3
すなわち is more formal and typically used in writing for definitions or equivalences, whereas と言うことは is common in everyday spoken conversation for drawing conclusions.

Politeness

ってことはplain
ってことは is the casual, contracted spoken form, while ということは is the standard, neutral-polite way to say the same thing.

Written forms

と言いうことは
Kanji form with 言う; the kana form ということは is more common in practice.
と言いう事ことは
Variant using 事 for こと; less common than the kana form.

Etymology

Phrase composed of the quotative particle と, the verb 言う (to say), the nominalizer こと, and the topic marker は. Literally 'as for the thing (one) says', it developed into a conjunction-like expression meaning 'that is to say' or 'so that means'.