taffrail
Concise Oxford English Dictionary © 2008 Oxford University Press:
taffrail/ˈtafreɪl/
▶noun a rail round a ship's stern.
– origin C19: alt. (by assoc. with rail1) of obs. tafferel ‘panel’, used to denote the flat part of a ship's stern above the transom, from Du. tafereel.
'taffrail' also found in these Oxford entries:

