Sentence:  And the bed that sagged in a certain place where all the weight had been put too many times before and the <WSD>walls</WSD> fine and thin for overhearing talk in the next room when Gratt went out for ice , the sound coming through the walls like something on the other side of the curtain , so you knew they heard you when they were quiet and while you lay wondering what they had heard you listened . 
Meaning of the word marked with <WSD> tags:  an architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure