(1):
(n.) The act of formally making persons known to each other; a presentation or making known of one person to another by name; as, the introduction of one stranger to another.
(2):
(n.) A formal and elaborate preliminary treatise; specifically, a treatise introductory to other treatises, or to a course of study; a guide; as, an introduction to English literature.
(3):
(n.) The act of introducing, or bringing to notice.
(4):
(n.) That part of a book or discourse which introduces or leads the way to the main subject, or part; preliminary; matter; preface; proem; exordium.