Estimated Time of Departure or Delivery (ETD)

ETD stands for Estimated Time of Departure or Delivery, depending on the context. 

Estimated Time of Departure refers to the expected time when a flight, train, bus, or ship is scheduled to leave a specific location, such as an airport or a transportation hub. 

ETD can change due to various factors, such as weather, mechanical issues, or air traffic control delays, so it is often updated in real time. A flight might show an ETD of 10:00 AM, but bad weather could cause a delay, updating the ETD to 10:30 AM.

Estimated Time of Delivery is the expected arrival time of goods or documents. For example, if a tour operator ships tickets, documents, or travel gear to clients, they will give an ETD for the expected delivery time of the package.