Webster's English Dictionary

salutation

sal.u.ta.tion \.sal-y*-'ta--sh*n\ \-shn*l, -sh*n-*l\ n 1: an act or action 
   of expressing greeting, goodwill, or courtesy by word,  gesture, or 
   ceremony 2: the word or phrase of greeting (as Gentlemen or Dear Sir) th at 
   conventionally comes immediately before the body of a letter - 
   sal.u.ta.tion.al aj