Realtors use the term “Chef Kitchen” all the time (sometimes further embellished with the adjective, “Gourmet” — as in, “Gourmet Chef Kitchen”).
But, after almost 17 years selling homes, I’m still not sure that I have a good definition, except that: a) it’s big; and b) it’s full of high-end features and appliances.
That includes granite or similarly high-end countertops; appliances like Subzero or Wolf — often doubled up (e.g., two fridges, two dishwashers, etc.); double sinks; a separate stove top with 6 or even 8(!) gas burners; custom cabinetry, lighting and flooring (either tile or hardwood); plenty of storage, both in cabinets (ideally 42″ or higher) and a nearby Pantry; a deluxe exhaust hood and fan; and a generous eat-in area and center island.
Plus, ideally, lots and lots of windows and natural light (of course) . . .