Decorum (noun)

1. The state or quality of being seemly, appropriate, or respectable in conduct or appearance.
2. A sense of propriety or suitability in social behavior, manners, and appearance.

Origin:

From the latin word "decorus" meaning "seemly, fitting, proper".

Examples:

1. The ceremony was conducted with great decorum.
2. The judge maintained decorum in the courtroom at all times.
3. The children were reminded to mind their decorum during the school assembly.
4. His decorum was impeccable even under the most trying of circumstances.
5. The decorum of the meeting was disturbed by a few unruly participants.