aro. is a term that may refer to various business or logistical operations, but it is commonly associated with shipping or fulfillment services, where ARO stands for “After Receipt of Order.” This term is often used to indicate the time it takes for a company to fulfill an order after it has been received. For example, if an order is shipped 3 days ARO, it means that the shipment will leave the warehouse 3 days after the order is received.