HORSEBACK
horseback, ahorse, ahorseback
(adverb) on the back of a horse; “he rode horseback to town”; “managed to escape ahorse”; “policeman patrolled the streets ahorseback”
horseback
(noun) the back of a horse
hogback, horseback
(noun) a narrow ridge of hills
Source: WordNet® 3.1
Etymology
Noun
horseback (plural horsebacks)
(usually with on, upon, etc.) The back of a horse.
A ridge of sand, gravel, and boulders.
Synonyms
• (ridge): esker
Adverb
horseback (not comparable)
On the back of a horse.
Synonyms
• ahorse, ahorseback, on horseback
Anagrams
• backshore
Source: Wiktionary
Horse"back`, n.
1. The back of a horse.
2. An extended ridge of sand, gravel, and bowlders, in a half-
stratified condition. Agassiz. On horseback, on the back of a horse;
mounted or riding on a horse or horses; in the saddle.
The long journey was to be performed on horseback. Prescott.
Source: Webster’s Unabridged Dictionary 1913 Edition