Originally Posted by Dominic Mazoch:
OK, "O" is from the number 0, HO is half 0. But where did the term "S" come from?
Legend has it from the S in Three-"S"ixteenths.
Originally "Half-One" in the UK.
In the US, it was originally it was called "C-D" scale, for Cleveland Design due to Cleveland Model and Supply being the first US company to produce kits in 3/16" scale.
Read all about it, the US portion is about 1/3 the way down:
http://www.s-scale.org.uk/history.htm
Rusty