In 1875, an American songwriter named [H.C. Work] Henry Clay Work was visiting England then wrote a song “My Grandfather’s Clock” that sold over a million copies in sheet music.
“My Grandfather’s Clock.” It went like this:
My grandfather’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,
It was always his treasure and pride;
But it stopped short
Never to go again,
When the old man died.
And the term grandfather clock became attached to the kind of clock that inspired the song. Visit this link for the whole story.