is a specific kind of: point, point in time.

is a broader term that covers: birth | incipience, incipiency | starting point, terminus a quo | threshold.

is the opposite of: middle | end, ending.

derivation: begin, commence, get, get down, set about, set out, start, start out | begin, commence, lead off, start | initiate, originate, start | commence, embark on, start, start up | start, take up | inaugurate, kick off | begin, start.