やNon-exhaustive noun listing
や joins nouns as representative examples, meaning “things such as A and B.” The list remains open, so other unnamed items may also be included.
The list is not complete
Use や when the named nouns are examples rather than the complete inventory. English translations often use “A, B, and so on,” “things like A and B,” or simply “A and B” when the open-ended meaning is already clear.
スーパーでパンや卵を買いました。
I bought bread, eggs, and a few other things at the supermarket.
AnalyzeLiterally: I bought things such as bread and eggs at the supermarket.
Put the next particle after the whole list
When the complete list is the object, subject, topic, or another part of the sentence, the particle marking that role normally comes after the final noun. In the example above, を follows the entire list, not its first item.
机の上に本やノートなどがあります。
There are books, notebooks, and other things on the desk.
AnalyzeOpen list versus complete list
や leaves other members unstated. By contrast, と presents the named nouns as the complete relevant list. Choose according to whether you mean “these examples, among others” or “these items, and no others relevant here.”
More examples
朝はパンや果物を食べます。
In the morning, I eat things like bread and fruit.
Analyze休日は読書や料理を楽しみます。
On my days off, I enjoy activities such as reading and cooking.
Analyze旅行には地図や薬などを持っていきます。
I take a map, medicine, and other useful things on trips.
Analyze教室には先生や学生が集まりました。
Teachers, students, and others gathered in the classroom.
Analyze引き出しにペンやはさみが入っています。
There are pens, scissors, and similar items in the drawer.
Analyzeデパートでシャツや靴を見ました。
I looked at shirts, shoes, and other items at the department store.
Analyze