What is the technical name for the little window that opens up between the kitchen/living areas of some homes?

Some call it a pass through

What is the technical name for the little window that opens up between the kitchen/living areas of some homes?
It is/was called a "serving window" and was used in households and houses where you had a kitchen staff and a wait staff. The kitchen staff placed food items in the serving window and the wait staff would serve at the table, and return the platters to the serving window where the kitchen staff would retrieve them. At least that is what I learned from seeing some of the bigger mansions in the small town where I grew up in Illinois. I, of course, lived on the wrong side of the tracks from the big houses. This window is now more of a simple decoration than a useful modification serving a useful purpose.
Reply:Yep, I call it a pass through, too.





If it's a above a doorway (or other high places), it's called a transom window -- was used in pre-airconditioning days to get a breeze through without having an open doorway.
Reply:"Pass-through"
Reply:food hatch