This is the 6th most frequent Japanese word.
と
The Japanese particle "と" is used to mean "and," "with," or to indicate a quotation or thought.
In this sentence, 'と' is used as a quotation particle to convey what was said.
彼は本を読んだと私に言いました。
He told me that he had read a book.
In this case, 'と' is used as a conditional to indicate that one action follows another.
海を見ると、安心します。
When I see the ocean, I feel at ease.
Here, 'と' is a conjunction that means 'and,' listing two items together.