v. Simple past tense and past participle of coffer.
The Century Dictionary and Cyclopedia
In architecture, built with coffers: said of a wooden ceiling or vault, the coffers in the former being the panels between the beams, and those of the latter being recesses built in the masonry.
Word Usage
"Now, I don't know about you, but when I conjure up a description of my bathroom or any bathroom, the words "coffered," "wainscoting" and "Bianco Verde marble" don't come to mind."