Astern

Behind a vessel or in the direction beyond its stern.

An object astern lies behind the vessel, while a vessel moving astern is travelling stern-first. An “astern” propulsion command requests thrust in the reverse direction, although the resulting motion and steering response depend on the vessel and existing way.

Astern is normally used as an adverb or adjective rather than a verb. It is distinct from “aft”, which describes a direction or location within the vessel towards its stern.