Not so! The volume measure "fluid oz" is the volume taken up by 1 oz of water by definition. There may be descrepancies between the weight and the volume with other fluids. I am sure that a fluid oz of motor oil might be lighter than an oz and a fluid oz of brine or syrup should be heavier but the definition of a fluid oz is the volume taken up by 1 oz (by weight) of water.

Pint is a pound the world around. Gotta love those brits for their measurement system! Start with a pint of guiness and work out from there!

I wonder if the horse is measured by the hand because after enough pints one must use the hand to "walk" yourself vertical before climbing into the saddle?