Sentence:  He also bought a huge <WSD>square</WSD> of pegboard for hanging up his tools , and lumber for his workbench , sandpaper and glue and assorted nails , levels and T squares and plumb lines and several gadgets that he had no idea how to use or what they were for . 
Meaning of the word marked with <WSD> tags:  (geometry) a plane rectangle with four equal sides and four right angles; a four-sided regular polygon