astern

taaksepäin

peränpuolelle, perässä, taakse

peräpuolella puhekieltä At, or any distance behind, the stern; further in that direction; backward (qualifier).
(quote-book)
puhekieltä behind Behind a vessel; having a bearing of 180 degrees from ahead.
If one ship is following another, the first is astern of the second.