to launch, begin, or undertake a course of action, to make a start or set out on something;
e.g. He has decided to embark on a new venture in an entirely unfamiliar field.
(verb)
to board a vehicle (such as a plane or a ship) in order to travel somewhere, or to take or put someone/something on board a vehicle for transportation;
e.g. We will embark on our journey in half an hour.