A markup is the difference between the retail price (the price at which they sell) and the cost (the price they pay). Broadly, it’s their profit.

A sales margin is the amount of profit you make on the sale of your products after all costs related to the item are accounted for (discounts, taxes, shipping…). The higher your sales margin, the higher your potential for profit on that product.

For the boutiques, it is the multiple between their cost and the retail price they are to sell your product for. They might accept a 2.0 markup (i.e.: selling at a 50% margin), but they actually want 2.2 (55% margin).

They only need to see the retail price and know their markup. Once they have that, they're ready to order just by looking at your samples!