Formality (noun)

1. A formal act, ceremony, or requirement.
2. A conventional social manner or behavior.
3. The quality of being formal or ceremonious.

Origin:

Middle english formalite, from middle french formalité, from latin formalitas, from formalis.

Examples:

1. The formality of the wedding was impressive.
2. The formality of the meeting was relaxed.
3. The formality of the greeting was a handshake.
4. The formality of the occasion demanded a suit and tie.
5. The formality of the negotiations was professional.