"[...] master bedroom is the just largest bedroom in the home [...]"
"[...] Master suite just means there is private bath. It can also include other amenities, but the bathroom is enough to call it a master suite. [...]"
"The master suite is usually the largest bedroom in the house, where the head of the household sleeps and provides more amenities than the other bedroom(s). Amenities may include a private bath accessible only from that bedroom, dressing area, and closet. " (ref. 1)

"Often defined as the largest bedroom in the home, the master bedroom is normally occupied by the person or persons who serve as the heads of the household. It normally includes more amenities than smaller bedrooms in the home, and may include additional spaces that are directly accessible from the interior of the space. When this is the case, this bedroom is sometimes referred to as a master suite or an ensuite." (ref. 2)

In primul rand trebuie inteles clar ce inseamna master suite.

A master suite addition is a place to call your own — no kiddie toys, no teens hogging the bathroom — a heavenly space where you can bathe, dress, or simply relax in peace. But paradise doesn’t come cheap.
http://www.houselogic.com/home-advice/master-suites/evaluate...

The master suite is evolving: it's becoming the place to recharge or unwind by enjoying five-star hotel amenities at home. Some examples include bathrooms that resemble spas with double vanities, ample storage, a whirlpool tub, and a spacious shower. Do you want the Master Bedroom adjacent to other bedrooms, or separated for privacy?
http://www.houseplans.com/collection/themed-master-suite-and...

In the last 20 years, the master bedroom has grown from a place to sleep into a status symbol. If you don't have a seating area in your bedroom, double sinks in the bath, a spa tub and a separate shower, you're nobody. And size matters.
http://realestate.msn.com/blogs/listedblogpost.aspx?post=a31...

Heidi and Roy Schoeneck are turning their unfinished attic into a relaxing master suite. With the help of contractor Drew Bruozis, this space gets a complete overhaul including a new floor, spa bathroom and historic stained-glass window.
http://www.hgtv.com/new-spaces/attic-master-suite/index.html

Deci, master suite este o suita de incaperi alaturate dormitorului matrimonial, incaperi accesibile exclusiv prin acest dormitor. Este o zona separata a unei case dar nu are bucatarie si nu are acces direct de afara.

Notiunea echivalenta in limba romana nu exista asa ca poate este momentul sa o ... inventam :-) In fond, chiar notiunea de master suite nu este mai veche de 25 de ani ...

Eu propun suita dormitrului matrimonial deoarece exact asta si este. Punctajul de 4 confdence pe care mi-l dau reflecta - pur si simplu - noutatea acestei propuneri, cu toate ca traducerea este data cu maxim de acuratete.

Personal, mai ales in real Estate, as evita confuziile de genul "apartament principal" deoarece asta duce direct la ideea de locuinta separata.


--------------------------------------------------
Note added at 4 days (2013-03-25 18:56:21 GMT)
--------------------------------------------------

Refugiu matrimonial, ansamblul dormitorului matrimonial s.a.m.d.
Dupa cum spuneam, o notiune impamantenita nu exista in limba romana. Pe de alta parte, folosirea expresiei "dormitor matrimonial" pentu o suita :-) de incaperi ... iar duce la confuzii.