Yours, Etc.: Origins and Uses of 8 Sign-Offs
late 14c., "act of bringing into existence," from Old French introduccion and directly from Latin introductionem (nominative introductio) "a leading in," noun of action from past participle stem of introducere "to lead in, bring in, to introduce," from intro- "inward, to the inside" (see intro-) + ducere "to lead" (see duke (n.)). Meaning "initial instruction in a subject; an introductory statement" is mid-15c. The sense of "formal presentation of one person to another" is from 1711.