and; such things as
Listing particle for non-exhaustive examples, often tied to a specific time and place. Softer than と.
机の上に本やペンがある。
There are books, pens, and such on the desk.
There are things like books and notebooks on the desk.
as soon as; the minute ...
Follows the dictionary form of a verb; often in the pattern や否や. Literary or formal.
See also: や否や
彼は家に着くや否や、電話をかけた。
He called as soon as he got home.
copula
Kansai dialect copula, equivalent to だ. Casual and regional.
See also: だ
これ、めっちゃうまいやん。
This is really good, isn't it? (Kansai)
Punctuational exclamation in haiku, renga, etc. Poetic and traditional.
古池や蛙飛びこむ水の音
The old pond—a frog jumps in, the sound of water. (Bashō)
Interjection expressing surprise or confusion. Casual.
や、何これ？
Huh? What's this?
Archaic interjection or question particle. No longer used in modern Japanese.
「や、さようにござります」と古い文に書いてある。
In old texts, you see things like 'Yes, that is so.'
ベルが鳴るや、生徒たちは教室を飛び出した。
The moment the bell rang, the students rushed out of the classroom.
と lists items exhaustively (this and only this), while や implies the list is incomplete, giving just a few examples.
だ is the standard Japanese copula, while や is its casual Kansai-dialect equivalent used the same way.
や is a more formal or written-style particle for listing a few examples, while とか is casual and can also add hearsay or vagueness.
や lists nouns non-exhaustively (like 'and' among other things), whereas たり lists actions or states and attaches to verb or adjective forms.
や connects items within a list, while など comes at the end of the list to signal that more unmentioned items exist.
Kana-only particle and interjection; no kanji spelling is used.
The particle や is native Japanese. The interjection and dialectal copula uses are also native, with the copula being a regional variant of だ.