Macy’s, the nation’s largest department store, is starting to compete with Amazon by offering same-day delivery in 17 markets. In order to do this, the retailer is using a delivery service called Deliv. In the same vein as Uber, Deliv is a startup that has a band of contracted delivery drivers on hand who pick up customers’ orders from a store, and then drop the orders off directly at the shipping address. Macy’s experimented with same-day delivery in eight markets last fall.