So bathroom is one word; but living room is written as two words.

Is bedroom a single word?

bedroom, bathroom, storeroom but living room, dining room, reading room. Both of them are really one word. The space between living and room is present only in writing; it's an artifact of the history of printing and has nothing to do with the English language.

Why is living room two words and bedroom is one?

Senior Member. Maybe because bed and bath are both nouns, whereas dining and living are both forms of a verb. If you had sleeping room (using verb to sleep) instead of bedroom it would be 2 words.