Utilizing Item Aliases can be extremely helpful. Aliases allow you to use multiple names (SKUs) for the same item. This helps when you and your manufacturer call the same part by different names or if you have a name for a part but call it something different for your customers.
Customer Facing - Different customers may have different names for the same item. You can list those under each item. Select your item. Edit the item details. Choose Customer Alias. And select the green add button.
Vendor Facing - The same may be true for Vendors. Your item may be called SEL-MAT-03 but the vendor may refer to the same item as 734592-01. Select your item. Edit the item details. Choose Vendors. And select the green add button. Here you can enter the vendor part number.
Manufacturer Facing - If you have an outside manufacturer who creates items that you sell and you call the item something different than the manufacturer this is how you manage that. You will open the item, select the alias tab then select the green add button.
If you do not see the Alias tab you need to go into the page layout for the Item Details and make the tab "Visible".