Forbes defines executive presence as:
The ability to project gravitas–confidence, poise under pressure and decisiveness—seems to be its core characteristic, according to more than two-thirds of the executives surveyed. Furthermore, communication—including speaking skills, assertiveness and the ability to read an audience or situation—and appearance contribute to a person’s perceived executive presence.
In this article by Forbes, Muriel Maignan Wilkins, coauthor of Own the Room, breaks executive presence into three essential parts.