Source : Webster's Revised Unabridged Dictionary (1913)

Etiquette \Et"i*quette`\, n. [F. prop., a little piece of paper,
   or a mark or title, affixed to a bag or bundle, expressing
   its contents, a label, ticket, OF. estiquete, of German
   origin; cf. LG. stikke peg, pin, tack, stikken to stick, G.
   stecken. See {Stick}, and cf. {Ticket}.]
   The forms required by good breeding, or prescribed by
   authority, to be observed in social or official life;
   observance of the proprieties of rank and occasion;
   conventional decorum; ceremonial code of polite society.

         The pompous etiquette to the court of Louis the
         Fourteenth.                              --Prescott.

Source : WordNet®

etiquette
     n : rules governing socially acceptable behavior