Množina: decorums
ETYM Latin decôrum, from decôrus. Related to Decorous.
Propriety in manners and conduct; SYN. decorousness.
Term derived from classical criticism meaning the proper or appropriate combination of elements within a work of art. Its later advocates believed that there was a “correct” style for each genre: grandiloquent for tragedy, low for comedy, and so on, and that these styles should never be mixed.