A cofferdam.
An ornamental sunken panel in a ceiling or dome.
A trench dug in the bottom of a dry moat, and extending across it, to enable the besieged to defend it with raking fire.
A strong chest or box used for keeping money or valuables safe.
A supply or store of money, often belonging to an organization.
To put money or valuables in a coffer
To decorate something, especially a ceiling, with coffers.
coffin