My wife wants to use the third bedroom as a guest room.

我妻子想把第三个房间做客房。

youdao

This room can be used as a library, study or media room or as a third bedroom.

这个房间可以用作图书馆、书房或媒体室，或作为第三间卧室。

youdao

We have our bedroom and I have my home office, and that third bedroom has been sitting unused…until now.

我跟我太太有间卧室，还有间家庭办公室跟第三间卧室，你知道一直没用......一直到现在。

youdao

As a purely practical matter, two small bathrooms are better than one large one and a third bedroom is more useful than a master suite.

FORBES: How To Get The Best Return On Your Home Renovations

For example: You are buying a 20-inch TV for a third bedroom that is going to be used more for looks, more then likely you do not need that warranty.

ENGADGET: HDTV Buying Guide: Extended Warranties HD

The main house also includes a two-bedroom third story and a finished basement with bar, game and laundry areas.

FORBES: Magazine Article