One name for each thing in your admin

"Web address" with the real path under it, "Cost per unit" and "Quantity" on every form, "register" at the counter, and no more dashes in empty cells.

Web address replaces "Slug" on products, pages, events, categories and sets. The line under it shows the path a buyer sees, in your shop's language, with the address you typed.
Cost per unit is the one name for what a unit cost you: on purchases, Add stock, the card page, Add cards, the phone scanner and the product import. Every count you type is Quantity.
Pickup is one word wherever it names something, like the Pickup type of a shipping method.
At the counter the POS speaks of the register and the order. The cash count says "Cash in the register".
View on a card's page opens the card on your shop at once. It no longer asks which copy, since every copy is on that one page.
"Add a copy" is the button's name too, like the window it opens.
Empty cells in lists are blank instead of a dash. Where a word helps, it says None, No role or Not yet.