1To enter, go in, or come in. The most basic everyday meaning — moving from outside to inside a room, building, vehicle, or area. The reading はいる centers on this sense.
靴を脱いで部屋に入ってください。
Please take off your shoes before entering the room.
電車にぎりぎり間に合って、ドアが閉まる前に入った。
I just barely made the train and got in before the doors closed.
雨が降ってきたから、急いで店に入ろう。
It's started to rain — let's hurry into the shop.
猫が窓から家に入ってきた。
A cat came into the house through the window.
プールに入る前にシャワーを浴びてください。
Please shower before getting into the pool.
2To join or enroll in an organization — a school, a company, a club, etc. Used for matriculation, getting hired, or joining a group: 大学に入る (enter university), 会社に入る (join a company), 部に入る (join a club).
妹は来年大学に入る予定だ。
My younger sister is planning to enter university next year.
新卒で大手商社に入った。
I joined a major trading company straight out of college.
高校では吹奏楽部に入っていた。
In high school I was in the brass band.
卒業後は政治の世界に入りたい。
After graduation I want to go into politics.
3To be contained or included in something — a category, a list, a container, a price. Typically used in the form 〜に入っている to describe being part of a set or counted within.
この値段に消費税は入っていますか？
Does this price include consumption tax?
あなたの名前は招待客リストに入っている。
Your name is on the guest list.
この箱には何が入っているの？
What's inside this box?
アボカドは野菜ではなく果物に入る。
Avocado is classified as a fruit, not a vegetable.
4To fit (in a container, room, etc.); to be physically accommodated. Carries a potential nuance — 入らない means "won't fit / not enough space."
このスーツケース、コートまで入りそうだ。
It looks like even my coat will fit in this suitcase.
ソファが大きすぎて、エレベーターに入らなかった。
The sofa was too big — it didn't fit in the elevator.
この会場は1000人ぐらいまで入る。
This venue holds about 1,000 people.
5To be introduced, brought in, or installed — a new system, feature, person, or piece of equipment being added.
今月から新しいシステムが入った。
A new system was introduced this month.
うちのチームに新しいデザイナーが入った。
A new designer has joined our team.
アップデートで便利な機能がいくつか入った。
Several useful features were added in the update.
6To come in as income — money, a payment, an order, profits. Used for paychecks being deposited, orders being received, revenue coming in.
今日、給料が口座に入った。
My salary was deposited in my account today.
新しい仕事の注文が次々に入っている。
New job orders keep coming in one after another.
副業で月に少し収入が入るようになった。
I've started getting a bit of monthly income from a side job.
7To be scored or registered — points, votes, marks. Used in sports (a goal going in), elections (votes coming in), and grading.
後半に逆転ゴールが入った。
A go-ahead goal was scored in the second half.
彼にはたくさんの票が入った。
He received a lot of votes.
あと一点入れば優勝だ。
One more point and we win the championship.
8(Of a device) to switch on or start functioning — power coming on, an engine kicking in, lights coming on.
停電のあと、ようやく電気が入った。
After the blackout, the power finally came back on.
古いパソコンは電源が入るまで時間がかかる。
Old PCs take a while to power up.
寒いから、もう暖房が入っているはずだ。
It's cold, so the heater should already be on.
9To enter a period, stage, or phase — entering a month or season, getting to the main topic, beginning negotiations or full-scale work. Marks a temporal or staged transition.
もう12月に入ったから、年末の準備を始めよう。
We're already in December — let's start year-end preparations.
前置きはこのへんにして、本題に入りましょう。
Let's leave the preamble there and get to the main point.
来週から新しいプロジェクトに入る。
I'll start working on a new project from next week.
話し合いは交渉の最終段階に入った。
The discussions have entered the final stage of negotiations.
10(Of a crack or fissure) to form or develop. The standard phrasing is ひびが入る or 亀裂が入る. Also used figuratively — ひびが入る can describe damage to a relationship or trust.
落としたグラスにひびが入ってしまった。
The glass I dropped got a crack in it.
あの一件で二人の友情にひびが入った。
That incident left a crack in their friendship.
11(Of effort, spirit, energy, or focus) to be put into something. Common in expressions like 力が入る ("to put strength into"), 気合いが入る ("to be fired up"), and 身が入る ("to be engaged in").
明日の試合に向けて、彼の練習はいつも以上に気合いが入っていた。
With tomorrow's match in mind, he was even more fired up than usual at practice.
緊張して手に力が入りすぎた。
I was so nervous I gripped too hard.
心配ごとがあって仕事に身が入らない。
I have something on my mind and can't focus on work.
12(Of tea, coffee, etc.) to be brewed and ready to drink. お茶が入る is the idiomatic way to say "the tea is ready / has been brewed."
お茶が入りましたよ、どうぞ。
The tea is ready — please help yourself.
コーヒーが入ったら呼んでください。
Let me know when the coffee is ready.
13(Of alcohol) to enter the body and start having an effect; to be tipsy or drunk. Often used in the form お酒が入ると〜 to describe how someone changes after a drink.
お酒が入ると、彼はよくしゃべるようになる。
Once he has a drink, he becomes very talkative.
少し入っただけで、もう顔が真っ赤だ。
He's only had a little, and his face is already bright red.