A general word for a thing or matter; can refer to concrete objects or abstract matters.
そのことを忘れないでください。
Please don't forget that (matter).
いいことと悪いことを区別する。
Distinguish between good things and bad things.
小さなことでも気になる。
Even small things bother me.
そのことについて詳しく教えてください。
Please tell me more about that matter.
An incident or occurrence; can imply an event, accident, or a serious/problematic matter.
交通事故のことを警察に知らせた。
I reported the traffic accident to the police.
それは大変なことになった。
That turned into a big problem.
事件のことは新聞に詳しく書かれている。
The incident is written about in detail in the newspaper.
Refers to circumstances, situation, or state of affairs surrounding something.
今のことをよく考えて決めなさい。
Think carefully about the current situation and decide.
経済のことが心配だ。
I'm worried about the economy/situation financially.
天候のことを考えると遠出は難しい。
Considering the weather, it's difficult to go far.
Refers to work, business, or affairs—matters to be handled or responsibilities.
家のことは私がやります。
I'll take care of the household matters.
会社の重要なことを上司に報告した。
I reported an important company matter to my boss.
銀行の手続きなど、面倒なことが多い。
There are many tedious things like bank procedures.
Attached to a noun or phrase to refer to the target in a slightly detached or objective way (often used when the speaker isn't emotionally close).
彼のことはよく知らない。
I don't know much about him.
あの人のことを噂するのはやめよう。
Let's stop gossiping about that person.
子どものことになると母親は厳しい。
When it comes to her children, the mother is strict.
A nominalizing suffix that turns verbs or adjectives into noun phrases (e.g., 'to do X' as a thing or fact).
日本語を勉強することは楽しい。
Studying Japanese is enjoyable.
早く行くことが必要だ。
It is necessary to go early.
食べることが好きだ。
I like eating.
病気のときは休むこと。
When ill, rest.
Used in constructions like '〜ことにする' or '〜ことにしている' to mean 'to pretend/decide to treat something as so' (e.g., to make-believe or decide to regard something as...).
彼は何も知らないことにしている。
He pretends not to know anything.
面倒だから、今日は行かないことにした。
Because it's troublesome, I decided not to go today.
An archaic/formal way to indicate an alias or alternate name in the form 'A こと B' (A = alias, B = real name); mainly used in formal documents.
山田こと鈴木花子が代表を務めます。
Yamada, also known as Suzuki Hanako, will serve as the representative.
旧姓の場合は『佐藤こと山田』と書くことがある。
In the case of a former name, it is sometimes written as 'Sato, also known as Yamada'.
Used in expressions like '〜ことはない' to indicate necessity (or lack thereof): 'there is no need to do ...'.
急ぐことはないよ。
There's no need to hurry.
そんなに心配することはない。
You don't need to worry that much.
行くかどうか迷っているなら、無理することはない。
If you're unsure about going, you don't have to force yourself.
Used in advisory or imperative constructions like '〜ことだ', meaning 'you should ...' or 'it's important to ...'.
試験前は毎日復習することだ。
Before exams, you should review every day.
健康のために早く寝ることだ。
You should go to bed early for your health.
彼に謝ることだ。
You should apologize to him.