An Essay on Criticism /decorum

de·co·rum (dĭ-kôr'əm, -kōr'-)
n.

1. Appropriateness of behavior or conduct; propriety: "In the Ireland of the 1940's ... the stolidity of a long, empty, grave face was thought to be the height of decorum and profundity" (John McGahern).
2. decorums The conventions or requirements of polite behavior: the formalities and decorums of a military funeral.
3. The appropriateness of an element of an artistic or literary work, such as style or tone, to its particular circumstance or to the composition as a whole.

 'Tis not enough no harshness gives offense;
The sound must seem an echo to the sense.

• Line 162.

Soft is the strain when zephyr gently blows,
And the smooth stream in smoother numbers flows;
But when loud surges lash the sounding shore,
The hoarse rough verse should like the torrent roar.
When Ajax strives some rock's vast weight to throw,
The line too labours, and the words move slow:

An Essay on Criticism was the first major poem written by the English writer Alexander Pope (1688-1744).

[Latin decōrum, from decōrus, becoming, handsome. See decorous.]

[名][U]

1 （行為・言葉・服装などの）端正さ, 礼儀正しさ；((〜s))礼儀作法

with decorum
礼儀正しく

forget decorum
礼を失する.

2 適切なもの；適切さ.