What is this symbol? `\eth`

Question

I was reading a LateX document about different symbols and found one called \eth: $\eth$.

Or very similar \dh

It's supposed to be a mathematical symbol, what does it mean?
It looks like a partial derivative but with a strike on it.

Answer 1

Nothing special, it is just a symbol. You can even define it as a natural number if you want. A symbol itself means nothing deep in mathematics.

As @Bye_World pointed out, people sometimes uses it to denote a differential operator, as the linked Wikipedia article shows.