intro.

noun
  1. 1

    The act or process of introducing.

    โ€œthe introduction of a new product into the marketโ€

  2. 2

    A means, such as a personal letter, of presenting one person to another.

  3. 3

    An initial section of a book or article, which introduces the subject material.

  4. 4

    A written or oral explanation of what constitutes the basis of an issue.

Source: https://en.wiktionary.org/wiki/intro., https://en.wiktionary.org/wiki/introduction