Why the name? 
Drat. I was gonna be a Smart Aleck and WAG that the term maker upper’s Grandfather had such a clock. And or, Everyones Grandfather had such a clock. :eek: And what do you know, I was right!
My thanks for all your help. 
There are also grandmother and granddaughter clocks, which are just shorter grandfather clocks.
The correct name for these is long case clocks. This what the experts on the Antiques Road Show always call them.
They and no one else.