My nephew at the dinner table tonight asked "Aunty why do they call this Horseradish sauce?" Mmmm! I couldn't answer him, but said I'd ask the AB. Any idea's?
The Ancient Greeks also used the radish (rhaphis in Greek) as an instrument of punishment for adulterers. They even had a verb 'to radish', which in the small lexicon used by schoolboys was defined as 'to punish as an adulterer' whilst the full lexicon (published in the 19C) defined it as 'to thrust a radish up the fundament'. Bet that made their eyes water!
I concluded years ago that 'horse' is a corruption of 'coarse'. Other examples are 'horse mushrooms' and 'horse chestnut', etc. Apparently the word 'cors' was used circa 1500 a.d. to mean 'ordinary'.