Beginning

of Begin

The act of doing that which begins anything; commencement of an action, state, or space of time; entrance into being or upon a course; the first act, effort, or state of a succession of acts or states.

That which begins or originates something; the first cause; origin; source.

That which is begun; a rudiment or element.

Enterprise.

the first part or section of something; "‘It was a dark and stormy night’ is a hackneyed beginning for a story"