Crossword Genius

Sandwich crust in desk (4-3)

Ross

I believe the answer is:

roll-top

I'm a little stuck... Click here to teach me more about this clue!

'desk' is the definition.
(I've seen this before)

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for roll-top that I've seen before include "Sort of desk" , "Type of desk" , "Trollop! (anag)" .)

Want a hint initially instead of a full solution? Install my app