Quick answer
Ва́нная is literally “the bath one” — the noun ко́мната dropped away. It still declines as an adjective: в ва́нной.
The common ones
| Word | Means | Implied noun |
|---|---|---|
| ва́нная | bathroom | ко́мната |
| приёмная | waiting room | ко́мната |
| приме́рочная | fitting room | каби́на |
| второ́е | main course | блю́до |
| пе́рвое | first course, soup | блю́до |
| моро́женое | ice cream | блю́до |
| больно́й | the patient | челове́к |
| ру́сский | a Russian | челове́к |
They keep adjective endings in every case: в ва́нной, на второ́е, с моро́женым, для больно́го. Never ва́нная ко́мната in speech — the adjective alone is the word.
At the table and at the doctor’s
Russian canteen menus are organised exactly this way: пе́рвое (soup), второ́е (main), тре́тье (the drink — usually compote), гарни́р (the side). Knowing the four words is enough to order a full lunch.
Nationalities
Ру́сский, неме́цкий and the rest are adjectives, but ру́сский doubles as the noun for a Russian man and ру́сская for a woman. Most other nationalities have proper nouns instead: не́мец / не́мка, англича́нин / англича́нка. Russian is the odd one out, and it trips people up.
The language too
Ру́сский on its own also means the Russian language, from ру́сский язы́к: Я учу́ ру́сский. Three meanings for one word — a Russian man, the language, and the adjective — all disambiguated by context.
Typical mistakes
в ва́нной ко́мнате — in speech
в ва́нной
The adjective alone is the normal word.
Я хочу́ моро́женый.
Я хочу́ моро́женое.
It is a neuter adjectival noun.
Check yourself
What does второ́е mean on a menu?