A farthing is a 1/4 of an old penny. However, there used to be 1/2 and
1/4 farthings. They date back to the 1800's. I've got a 1/2 farthing
in my collection at home but can't remember the details.
Now if you want to talk coins, there's the crown (5 shillings) 1/2
crown and the groat.
We had rods, poles, perches, chains and fathoms. All units of length.
Thank goodness we went metric.
If you really want to baffle folks, just mention Twaddle as a unit.

John