と

The particle と has two main uses:

• As a connector ("and")

  Used to list items, typically nouns, that are treated as a set. It implies that all listed items are included, leaving no room for ambiguity.

  りんごとばななバナナをかいました買いました。

  I bought apples and bananas.

  Here, it is clear that only apples and bananas were bought – no other items.

  や, on the other hand, connects items in a list but implies examples among a larger, unspecified group. It suggests that the listed items are not exhaustive.

  りんごやばななバナナをかいました買いました。

  I bought apples, bananas, and so on.

• As a marker for companionship or interaction ("with")

  Indicates that the action is performed together with someone or something.

  かぞく家族とりょこう旅行にいきます行きます。

  I will travel with my family.