1A conditional conjunctive particle linking two clauses so that whenever the first happens, the second naturally or inevitably follows. Often expresses automatic results or habitual outcomes ('if / when / whenever').
窓を開けると、涼しい風が入ってきた。
When I opened the window, a cool breeze came in.
このボタンを押すと、電気が消えます。
If you press this button, the light goes off.
春になると、桜が咲く。
When spring comes, the cherry blossoms bloom.
まっすぐ行くと、右に駅があります。
If you go straight, the station is on your right.
2A particle that joins nouns or noun phrases in an 'A と B' list, equivalent to 'and'. It implies an exhaustive list of all the relevant items, unlike や, which suggests a partial list.
りんごとみかんを買った。
I bought apples and tangerines.
犬と猫を飼っています。
I keep a dog and a cat.
田中さんと鈴木さんが来ました。
Mr. Tanaka and Mr. Suzuki came.
3A particle marking the person (or thing) one does something together with, or the counterpart of a reciprocal action such as talking, comparing, or fighting with ('with').
友だちと映画を見に行く。
I'm going to see a movie with a friend.
彼は父と暮らしている。
He lives with his father.
つまらないことで兄とけんかしてしまった。
I ended up fighting with my older brother over something trivial.
4A quotative particle that marks the content of speech or thought, appearing before verbs like 言う (say), 思う (think), or 書く (write). The quoted content comes before と.
彼は「行く」と言った。
He said, 「I'll go.」
もう無理だと思った。
I thought it was hopeless.
明日は雨が降るとニュースで言っていた。
The news said it would rain tomorrow.
5In shogi, a pawn that has been promoted after reaching the enemy's camp. Formally called と金 (tokin) and written on the board simply as と; it moves like a gold general.
端の歩が成って、と金が相手の王を追い詰めた。
The pawn on the edge promoted, and the tokin cornered the opponent's king.
と金は金と同じ動きができるので、攻めに強い。
A tokin moves like a gold general, so it's powerful on the attack.
6A sentence-final particle in the Kyushu dialect that turns a sentence into a question, roughly equivalent to standard 〜の?. Casual and strongly regional.
今日、行くと？
Are you going today? (Kyushu dialect)
これ、食べていいと？
Is it okay to eat this? (Kyushu dialect)