horseback UK /ˈhɔːsˌbæk/US /ˈhɔɹsˌbæk/noun 2adverb 1forms 1phrases 1 noun2 •The back of a horse.They came on horseback across the plains. •A ridge of sand, gravel, and boulders. adverb1 •On the back of a horse. formshorsebacks Phrases with horseback horseback opinionAn opinion given without thorough consideration or a firm basis, often used in a casual or speculative way.
