What is this sign _ called?

What is this sign _ called?

Thanks

It's a typography question rather than a language one. I don't know how underscore is called.

It's called an underscore.

or a underdash

Who calls it underdash?

You do obviously.

<<What is this sign _ called?>>

The term is definitely "underscore".

<<Who calls it underdash?>>

That reminds me of "balderdash". ;-)