noun
thing; matter; the fact that; doing
Very common abstract noun and formal noun. It refers to a matter, topic, fact, or action rather than a concrete object; after a verb or adjective phrase, it nominalizes the phrase as an abstract thing.
そのことは、あとでゆっくり話しましょう。
Let's talk about that matter later.
日本語を勉強することが好きです。
I like studying Japanese.
noun
incident; event; trouble; crisis
Used for something that happens, especially when it is serious, troublesome, or potentially bad. Common in phrases such as 大変なこと and もしものこと.
大変なことが起きた。
Something serious happened.
もしものことがあったら、この番号に電話してください。
If anything happens, call this number.
noun
circumstances; situation; state of affairs
Refers to how matters stand or how a situation has developed. Often appears in set expressions such as ことの次第.
ことの次第を説明してください。
Please explain the circumstances.
noun
Used for someone's duties, household matters, company affairs, or other practical business to be handled.
家のことは兄が全部やっている。
My older brother handles all the household affairs.
会社のことは彼に任せてあります。
Company affairs have been left to him.
noun, used as a suffix
make-believe; pretending to
Limited suffix use, mostly encountered in fixed compounds where こと is voiced to ごと, such as ままごと. It is not a freely productive modern standalone use.
See also: 事 (ごと)
子どもたちはままごとをして遊んでいる。
The children are playing house.
noun
also known as; real name; alias
In the pattern AことB, A as an alias and B as the real name. This is common in explanatory or news-like writing.
怪盗Xこと山田太郎が逮捕された。
The thief known as Kaito X, whose real name is Taro Yamada, was arrested.
noun
no need to; not necessary to
Used in the pattern verb dictionary form + ことはない to say that there is no need to do something.
そんなに心配することはない。
There is no need to worry so much.
noun
should; it is important to; I advise that
Used in the pattern verb dictionary form + ことだ to give advice or state what is important. It can sound direct or explanatory.
まずは自分で調べてみることだ。
First, you should try looking it up yourself.