A conditional particle meaning 'if' or 'when' that often indicates that one action/situation inevitably leads to the next.
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.
ボタンを押すと、電気が消える。
If you press the button, the light goes off.
日本に行くと、毎回ラーメンを食べる。
When I go to Japan, I eat ramen every time.
A particle meaning 'and' used to list or connect nouns/phrases.
りんごとみかんを買った。
I bought apples and tangerines.
彼と彼女は友達だ。
He and she are friends.
ペンとノートを忘れないでください。
Don't forget your pen and notebook.
A particle meaning 'with' to indicate accompaniment or sometimes means/manners (go with someone / do something with something).
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.
日本語の先生と相談したほうがいい。
You should consult with your Japanese teacher.
A quotative particle used to mark speech or thought (used in phrases like 'said that...' or 'thought that...').
彼は『行く』と言った。
He said, 'I'll go.'
『面白い』と思ったと彼女は笑った。
She smiled and thought, 'That's interesting.'
先生が明日休む、と連絡があった。
There was a message that the teacher will be off tomorrow.
In shogi, the promoted pawn (commonly abbreviated as 'と'; formally called 'と金').
端の歩が成って、と金が相手の王を追い詰めた。
A pawn on the edge promoted, and the promoted pawn (tokin) cornered the opponent's king.
とをうまく使って勝ちに持ち込んだ。
He used the tokin skillfully to secure the win.
A sentence-ending particle in Kyushu dialect used to indicate a question; regional and informal.
今日、行くと？
Are you going today? (Kyushu dialect)
それ、ほんとにするっと？
Are you really going to do that? (colloquial/dialectal)