The cut refers to either and both :
1. the cut length of fabric is the total amount you need for your complete project and which is cut by the seller from a full or part roll of their stock. This cut is the total of all the cuts needed to make the work (b)
2. each cut length of curtain or piece of a pattern that you need to get in order to make the work, the addition of which gives you the quantity for (a) and that you then need to cut from the piece of fabric that you’ve bought in order to make the work.
In a) cut lengths carry a cutting cost–i.e. any fabric cut to order–is always proportionately more expensive than buying a whole roll.
In b) knowing the cuts at quotation stage also allows you to manipulate the fabric when it comes to making it up – that may be around flaws, or needing to buy two shorter lengths than one long one short lengths, or when you want to use more than one fabric in a full or part patchwork scheme.