[Grammar] Xerosis is a technical medical term "for what" most people refer to as dry skin.

[yar7923]

Xerosis is a technical medical term "for what" most people refer to as dry skin.

Xerosis is a technical medical term for what most people refer to as dry skin.

This was a grammar question and I chose a wrong option : 'for which' instead of 'for what'.
Could you please explain why the answer is so?

Thank you in advance.

 

[Raymott]

Re: Xerosis is a technical medical term "for what" most people refer to as dry skin.

'What' here means 'that which'. It often does.

"I know what I know." = "I know that which I know."

 

[yar7923]

Re: Xerosis is a technical medical term "for what" most people refer to as dry skin.

Sorry I don't understand your explanation.. plus I thought 'that' and 'which' can't be used together.

 

[Raymott]

Re: Xerosis is a technical medical term "for what" most people refer to as dry skin.

• [h=4]what pronoun (THAT WHICH)[/h]

B1​

the thing(s) that; that which:What I ​wanted to ​find out first was how ​long it was going to take.What really ​concerned her was how ​unhappy the ​child was.She wouldn't ​tell me what he said.I didn't have much ​money on me but I gave them what I had.The ​letter ​showed ​clearly what they were ​planning.I can't ​decide what to do next.Have you ​thought about what to ​send as a ​present?

http://dictionary.cambridge.org/dictionary/english/what