Sentence:  My <WSD>grandfather</WSD>'s clock was too large for the shelf.— / So it stood ninety years on the floor; / It was taller by half than the old man himself, / Though it weighed not a pennyweight more. / It was bought on the morn of the day that he was born, / And was always his treasure and pride; / But it stopp'd short—never to go again— / When the old man died. 
Meaning of the word marked with <WSD> tags:  A father of someone's parent. (from 15th c.)