Have you noticed over the past few years how the adjectival term "en suite" has increasingly been used as a noun? e.g. "Master bedroom with ensuite", instead of "with en suite bathroom".
Of course, the term comes from the French and means "in, or as part of, a series, or set."
I blame it on estate agents, who began by using the term correctly, but then dropped the word 'bathroom'.
This advertisement of a house for sale in Worksop manages to include both usages:
"The property, a former show home benefits from spacious family living accommodation which in brief includes reception hall, WC, study, full length lounge, spacious dining room, breakfasting kitchen and utility room. On the first floor there is a master bedroom suite with dressing room and en suite bathroom, guest bedroom with en suite, three further bedrooms and a family bathroom."
Apparently the term "ensuite" is not used in the United States:
"Americans who have wandered chilly London hallways in the middle of the night in search of a toilet will appreciate learning the peculiar British meaning of the word “ensuite.”
In French, a set of two rooms or more forming a single accommodation can be advertised as rooms en suite (forming a suite).
But the single word French word 'ensuite' means something entirely different: “then, later.”
Around the middle of the 20th century English landlords and hoteliers began to anglicize the phrase, placing it before the noun, so that traditional “rooms en suite” became “en suite rooms,” Ads read “bath ensuite” or “toilet ensuite” as if the phrase meant “in the suite.”
The phrase “en suite” came to be used solely to designate bathrooms attached to a bedroom.
Following standard English patterns, they hyphenated the phrase as “en-suite bath” and often made the phrase into a single word: “ensuite bath.”
These have become standard British usage; but hoteliers often go a step further by writing “all rooms ensuite” (Americans would write “all rooms with bath”)."
(From "Common Errors in English" by Paul Brians)

Bushka
Pro
I have noticed///and find it sticks in my throat when I want to use it as a noun....