Butler’s Pantry vs Butler’s Kitchen: How a Pantry, Scullery and Prep Kitchen Differ

What is a butler’s pantry, and is a butler’s kitchen the same room? Merriam-Webster defines the first as a service room between kitchen and dining room; I found no definition of the second. Here is how a butler’s pantry, scullery, walk-in pantry and prep kitchen differ, what Whitehall and Biltmore show about the original, NKBA’s aisle and sink guidelines, what the MLS can and cannot say, and what conveys under the ASIS-7x contract.