de ‧ co ‧ rum /dɪˈkɔːrəm/ BrE AmE noun [uncountable]
[ Date: 1500-1600 ; Language: Latin ; Origin: decorus ; ⇨ ↑ decorous ]
formal behaviour that shows respect and is correct for a particular situation, especially a formal occasion:
He was disciplined for breaching the Senate’s rules of decorum.