Dropshipping is a retail order fulfillment method using a third party supplier such as Oberlo or Dropshyp without holding any inventory. A store does not stock the products it sells, instead when the store sell a product, it only send the order information as shipping information to the third party supplier The actual product supplier ships out the product without the supplier identifying information to the buyer and the tracking number about the order to the dropshipper.
The biggest difference between dropshipping and the standard retail model is that the merchant doesn't need to stock or own the products. Instead, the merchant purchases products after the order placed from a third party (a wholesaler or manufacturer) to fulfill orders.