punctilio

A fine point of etiquette.

Precise observance of formalities.

A small point.

A nice point, especially in conduct, ceremony, or proceeding; also, particularity or exactness in the observance of forms.

A nice point of exactness in conduct, ceremony, or proceeding; particularity or exactness in forms.

A fine point in exactness of conduct, ceremony or procedure. Strictness in observance of formalities.

a fine point of etiquette or petty formality

strict observance of formalities