Knock has a certain onomatopoeia, does it not?

Yes, to me, it sounds like knuckles hitting a hollow door with an empty foyer on the inside.

the D&D Spell does… it’s used to open doors

Yes, it does.
But in written text I think it would be onomatopoeia when it is written twice : Knock,knock

Let’s see. knock knock knock “I’m from the Government and I’m here to help.”

Yep, you got a good point there.

The etymology of “knock” probably is onomatopoeic, actually.

Way more then tintinnabulation does!

Side note… you reminded me of the exact same word in Thai, “kór.” Maybe other languages also have their onomatopoeia word for “knock.”

@longtresses They definitely do. Wikipedia lists quite a series of examples.

@ETpro Great list! Thank you.