Definition of introduction noun from the Oxford Advanced Learner's Dictionary
bringing into use/to a place
1[uncountable]the act of bringing something into use or existence for the first time, or of bringing something to a place for the first timethe introduction of new manufacturing methodsthe introduction of compulsory military servicethe 1000th anniversary of the introduction of Christianity to Russia2[countable]a thing that is brought into use or introduced to a place for the first timeThe book lists plants suitable for the British flower garden, among them many new introductions.
3[countable]introduction (to somebody)the act of making one person formally known to another, in which you tell each the other's nameIntroductions were made and the conversation started to flow.Our speaker today needs no introduction(= is already well known).a letter of introduction(= a letter which tells somebody who you are, written by somebody who knows both you and the person reading the letter)
4[singular]introduction (to something)a person's first experience of somethingThis album was my first introduction to modern jazz.
5[countable, uncountable]introduction (to something)the first part of a book or speech that gives a general idea of what is to followa brief introductiona book with an excellent introduction and notesBy way of introduction, let me give you the background to the story. compare preface
6[countable]introduction (to something)a book or course for people beginning to study a subject‘An Introduction to Astronomy’It's a useful introduction to an extremely complex subject.
7[countable] (music) a short section at the beginning of a piece of musican eight-bar introduction