rearhorse
/ˈriːrˌhɔrs/Definitions
1. noun
A horse ridden by the rear or second rider in a pair of horsemen, typically in a ceremonial or symbolic procession.
“The rearhorse was decorated with intricate carvings and ornate saddles.”
2. noun
A horse that follows another horse, especially as part of a pair of horsemen.
“The rearhorse was struggling to keep up with the lead horse in the endurance ride.”