introductory statement; a brief talk before the main event
In the preamble to his acceptance speech he thanked his friends and family for having always encouraged him.
prae (before)#ambulare (to walk) (Latin)
PRE (before) + AM (i) + BOL (tell): in a meeting political leaders will say: what I want to say before I start my lecture is bla bla bla. All this will take 1 hour. :). This is what preamble is.