An abandoned cart email is a follow-up message sent to customers who have added items to their online shopping cart but did not complete the purchase. These emails are crucial as they remind customers of their intention to buy and encourage them to return to complete the transaction. Abandoned cart emails typically include a summary of the items left behind, and they may also provide incentives, such as discounts or free shipping, to entice customers back. This strategy can significantly reduce cart abandonment rates and recover potential lost sales, making it an essential part of any eCommerce email marketing approach.