Terminology used in ERP - Sales Order

Make To Order (MTS)

A module that take sales order from customer and it links to production module (MRP) for production. It can monitor the sale progress 

Make To Stock (MTS)

A module that acts much likely forcast the sales before the sales order come in. If your inventory house does not have much problem of handling the stock. Eg, out of space , easily get damaged and etc.. MTS should be practised more often.