Some one already said it but i will agree with them and repeat it as ameans of giving strenght to their answer through numbers living and dinning are both verbs and pretain to what is done in the room bedroom is a type of room characterized by the bed if you were to call it a sleeping room it would be two words bathroom is the same but wash room is two words if their is a verb.
Guest room one word or two.
Depending on how common they are.
There are tons of words in english that used to be two words.
A bedroom in a house for visitors to sleep in.
Frankly the right answer may only be right this year.
Meaning pronunciation translations and examples.
When in doubt use the hyphenate as it s in.
Synonyms for guest room include spare room bedroom boudoir chamber cubicle dorm dormitory room bedchamber and bunk room.
Next year it could have evolved.
Guest room definition is a bedroom for a person who is invited to visit or stay in someone s home.
Guest room definition a room for the lodging of guests.