What does 'On Order' and 'On Back Order' mean within the context of ordering in EZ Process Pro?

In EZ Process Pro, when an item is marked as "On Order," it indicates that the purchase order associated with that item has been placed but the item has not yet been received into inventory. Conversely, when an item is labeled as "On Back Order," it signifies that the item is awaiting fulfillment from the supplier and is currently sitting in the Items for PO section.