preroll

/P R R OW1 L/
noun
  1. 1

    A period of time during which the camera rolls but before the action begins.

  2. 2

    An advertisement that plays before the main content.

Synonyms

verb
  1. 1

    To roll something in advance.

  2. 2

    To make or show a preroll.

Source: https://en.wiktionary.org/wiki/preroll