introduction
in.tro.duc.tion \.in-tr*-'d*k-sh*n\ n [ME introduccioun act of introducing, fr. MF introduction, fr. L Xintroduction-, introductio, fr. introductus, pp. of introducere 1: something that introduces : as 1a1: a part of a book or treatise preliminary to the main portion 1a2: a preliminary treatise or course of study 1b: a short introductory musical passage 2: the act or process of introducing or the state of being introduced 3: a putting in : INSERTION 4: something introduced; specif : a new or exotic plant or animal
Webster's English Dictionary