Noun
shadbelly (plural shadbellies)
An old-fashioned formal dress coat sometimes worn in equestrian circles.
In upper-level classes, the riders wear a tailed jacket ( shadbelly ) with a yellow vest or vest points instead of a plain dressage coat. Source: Internet
The wearing of shadbelly or other tailcoat jackets is not compulsory in the dressage phase. Source: Internet
Upper level riders wear a shadbelly, white gloves, breeches, tall boots, and spurs. Source: Internet