The horse in horseradish, unfortunately, has nothing to do with equines. According to wikipedia, n english, in the 1590's, the word "horse" was used to mean "course" or "strong".

Art by whiteflyinglizard


haggadah Section: Maror
Source: https://www.deviantart.com/whiteflyinglizard/art/Horse-Radish-438126988