Sentence:  . Buy enough unperforated, rigid plastic <WSD>drainpipe</WSD> for the job at a building supply center; also buy a 90-degree <WSD>drainpipe</WSD> elbow, <WSD>drainpipe</WSD> couplings, and any adapter available to join the drainpipe and downspout. 
Meaning of the word marked with <WSD> tags:  The type of pipe that is used to construct a drainpipe.