caisson vs coffer

caisson and coffer both are nouns.

Word	Noun	Adjective	Verb	Adverb
caisson	Yes	No	No	No
coffer	Yes	No	No	No

As nouns, caisson and coffer are synonyms defined as:

Other synonyms of caisson include lacunar.

caisson (noun)	coffer (noun)
large watertight chamber used for construction under water	a chest especially for storing valuables
an ornamental sunken panel in a ceiling or dome	an ornamental sunken panel in a ceiling or dome
a chest to hold ammunition
a two-wheeled military vehicle carrying artillery ammunition