inauguration
formal ceremony to mark the beginning of a major public leader's term of office, or official opening or beginning of an institution or structure
en-US/ˌɪˌnɔɡjəˈɹeɪʃən/
en-GB/ɪˌnɔːɡjʊˈɹeɪʃən/
formal ceremony to mark the beginning of a major public leader's term of office, or official opening or beginning of an institution or structure