Sentence:  I strive, with wakeful melody, to cheer / The sullen gloom, sweet Philomel! like thee, / And call the stars to listen: every star / Is deaf to mine, enamour'd of thy <WSD>lay</WSD>. 
Meaning of the word marked with <WSD> tags:  A ballad or sung poem; a short poem or narrative, usually intended to be sung.