n. 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.n. That which is begun; a rudiment or element.n. That which begins or originates something; the first cause; origin; source.n. The initial portion of some extended thing.v. Present participle of begin.adj. Of or relating to the first portion of some extended thing.