usher in

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 <begin a trip> <began dancing>. start, opposed to stop, applies especially to first actions, steps, or stages <the work started slowly>. commence can be more formal or bookish than begin or start <commence firing> <commenced a conversation>. initiate implies taking a first step in a process or series that is to continue <initiated diplomatic contacts>. inaugurate suggests a beginning of some formality or notion of significance <the discovery of penicillin inaugurated a new era in medicine>. usher in is somewhat less weighty than inaugurate <ushered in a period of economic decline>.