Sentence:  We went into Mrs. Monmouth 's library , which had low bookshelves all along the <WSD>walls</WSD> , and above them a Modigliani portrait , a Jackson Pollock twelve feet long , and a gorgeous Miro with a yellow background , that looked like an inscription from a Martian tomb . 
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