Do both work?
I could only assume that both are grammatically correct…
As an example:
Let's say that there is a word that derives from a name, such as "sandwich" which was coined from a name of somebody.
But let's say that we want to ask the name of the person that it came from.
We would ask:
"Where does it come from?"
but I feel like that the phrase:
"What does it come from?"
is applicable and even more plausible when asking for the origins of words, as some might not have come from names or places.
Best Answer
In this case, if you know that it is named after a person you should use 'who is it named after?'. If you don't know 'where' is better than 'what', as 'where' is a place, and the use of 'coming from' fits with a 'place' (set of circumstances) from where the idea has come. If you want to use 'what', try 'what caused it to be called a sandwich?'.