coach-horsern.
Origin: Formed within English, by derivation. Etymons: coach-horse n., -er suffix1.
Etymology: < coach-horse n. + -er suffix1. Compare later horser n.Previous versions of the OED give the stress as: ˈcoach-horser.
1837 C. Dickens xlii. 463 The embarrassed coach-horser was ordered to be discharged forthwith.
This entry has not yet been fully updated (first published 1891; most recently modified version published online December 2020).