What is an inventory item?
An inventory item is Shopify's inventory record for a sellable item.
In SKU Stock Sync, inventory items are important because Shopify tracks available stock for inventory items at each Shopify location.
In most Shopify stores, you can think of an inventory item as the stock record connected to a product variant.
Why inventory items matter
SKU Stock Sync uses inventory items when checking and updating stock.
When Shopify shows an available quantity for a variant at a location, that quantity is tracked through the inventory item at that location.
How this relates to members and groups
Inside SKU Stock Sync, an inventory item can be a member of a group.
A group is made from inventory items that share the same SKU at the same Shopify location.
Inventory items are the stock records SKU Stock Sync works with. Groups are how the app decides which inventory items should stay aligned.
Short answer
An inventory item is Shopify's stock record for an item, tracked per location.