The word etiquette, from the French word for label, is defined in the dictionary as “...the forms, manners, and ceremonies established by convention as required in society.” In philatelic terms, this includes advisory labels placed on mail to accomplish or expedite delivery. The best known is the airmail etiquette. Others include advisories for Express, Registration, and some unusual ones like Fragile and Eggs.
Information regarding etiquettes may be found in The Revealer, the official publication of the Eire Philatelic Association. A searchable CD ROM of the first 50 years of The Revealer is available through the Special Offers Manager.