hatchment
Concise Oxford English Dictionary © 2008 Oxford University Press:
hatchment/ˈhatʃm(ə)nt/
▶noun a large diamond-shaped tablet bearing the coat of arms of someone who has died, displayed in their honour.
– origin C16: prob. from obs. Fr. hachement, from OFr. acesmement ‘adornment’.
'hatchment' also found in these Oxford entries:

