from dogs, obviously. look at them. nothing else could possibly be named 'dog'

the dog thing is extremely interesting to me because it's apparently also the case for Polish, where any research also gives me only "so here are possible etymologies but there is no consensus", despite the Polish word for dog - "pies" - having seemingly nothing in common with the English equivalent

I love when we completely lose the etymology for what's honestly not that old of a word. A thousand years is pretty young for this!

The etymology of "Idaho" is fascinating. It appears to be just a made-up word by a huckster who kept trying to name various things (like a steamship) "Idaho" because I guess he just liked the word? He tried to get Colorado called Idaho but his ruse was discovered, and then later accidentally succeeded in getting a different state named Idaho anyway.
https://en.wikipedia.org/wiki/Idaho#Etymology

Fun fact about "dog" as the word for the domesticated canine: the Mbabaram language (Australian Aboriginal language from the northeast of the continent) has the word "dúg" for that animal, pronounced almost exactly like the Australian English pronunciation of "dog". This was very confusing for linguists for a bit, who thought it might have been borrowed from English.

We don't know where the word "dog" comes from, but it's at least possible that it basically means "who's a good boy?", as is good and right.