usher in

verb

  1. to serve to bring into being

  2. to mark or observe the beginning of

a discovery that ushered in a period of change

begin commence start initiate inaugurate usher in mean to take the first step in a course, process, or operation. begin, start, and commence are often interchangeable. begin, opposed to end, is the most general. start, opposed to stop, applies especially to first actions, steps, or stages.